diff --git a/pymisp/__init__.py b/pymisp/__init__.py
index 73f1be8..ca0868d 100644
--- a/pymisp/__init__.py
+++ b/pymisp/__init__.py
@@ -39,7 +39,7 @@ try:
                             MISPNoticelist, MISPObjectTemplate, MISPSharingGroup, MISPRole, MISPServer, MISPFeed,
                             MISPEventDelegation, MISPUserSetting, MISPInbox, MISPEventBlocklist, MISPOrganisationBlocklist,
                             MISPEventReport, MISPCorrelationExclusion, MISPDecayingModel, MISPGalaxy, MISPGalaxyCluster,
-                            MISPGalaxyClusterElement, MISPGalaxyClusterRelation)
+                            MISPGalaxyClusterElement, MISPGalaxyClusterRelation, MISPNote, MISPOpinion, MISPRelationship)
     from .api import PyMISP, register_user  # noqa
     # NOTE: the direct imports to .tools are kept for backward compatibility but should be removed in the future
     from .tools import AbstractMISPObjectGenerator  # noqa
@@ -76,7 +76,8 @@ __all__ = ['PyMISP', 'register_user', 'AbstractMISP', 'MISPTag',
            'MISPEventDelegation', 'MISPUserSetting', 'MISPInbox', 'MISPEventBlocklist',
            'MISPOrganisationBlocklist', 'MISPEventReport', 'MISPCorrelationExclusion',
            'MISPDecayingModel', 'MISPGalaxy', 'MISPGalaxyCluster', 'MISPGalaxyClusterElement',
-           'MISPGalaxyClusterRelation', 'PyMISPError', 'NewEventError', 'NewAttributeError',
+           'MISPGalaxyClusterRelation', 'MISPNote', 'MISPOpinion', 'MISPRelationship',
+           'PyMISPError', 'NewEventError', 'NewAttributeError',
            'NoURL', 'NoKey', 'InvalidMISPObject', 'UnknownMISPObjectTemplate', 'PyMISPInvalidFormat',
            'Distribution', 'ThreatLevel', 'Analysis', 'ExpandedPyMISP'
            ]
diff --git a/pymisp/exceptions.py b/pymisp/exceptions.py
index a0dd736..071d350 100644
--- a/pymisp/exceptions.py
+++ b/pymisp/exceptions.py
@@ -23,6 +23,21 @@ class NewEventReportError(PyMISPError):
     pass
 
 
+class NewAnalystDataError(PyMISPError):
+    pass
+
+
+class NewNoteError(PyMISPError):
+    pass
+
+
+class NewOpinionError(PyMISPError):
+    pass
+
+class NewRelationshipError(PyMISPError):
+    pass
+
+
 class UpdateAttributeError(PyMISPError):
     pass
 
diff --git a/pymisp/mispevent.py b/pymisp/mispevent.py
index 9bab316..34dec2c 100644
--- a/pymisp/mispevent.py
+++ b/pymisp/mispevent.py
@@ -23,13 +23,65 @@ except ImportError:
     import json
 
 from .abstract import AbstractMISP, MISPTag
-from .exceptions import (UnknownMISPObjectTemplate, InvalidMISPGalaxy, InvalidMISPObject,
+from .exceptions import (NewNoteError, NewOpinionError, NewRelationshipError, UnknownMISPObjectTemplate, InvalidMISPGalaxy, InvalidMISPObject,
                          PyMISPError, NewEventError, NewAttributeError, NewEventReportError,
-                         NewGalaxyClusterError, NewGalaxyClusterRelationError)
+                         NewGalaxyClusterError, NewGalaxyClusterRelationError, NewAnalystDataError)
 
 logger = logging.getLogger('pymisp')
 
 
+class AnalystDataBehaviorMixin(AbstractMISP):
+
+    # NOTE: edited here must be the property of Abstract MISP
+
+    def __init__(self) -> None:
+        super().__init__()
+        self.uuid: str  # Created in the child class
+        self.classObjectType: str  # Must be defined in the child class
+        self.Note: list[MISPNote] = []
+        self.Opinion: list[MISPOpinion] = []
+        self.Relationship: list[MISPRelationship] = []
+
+    @property
+    def notes(self) -> list[MISPNote]:
+        return self.Note
+
+    @property
+    def opinions(self) -> list[MISPOpinion]:
+        return self.Opinion
+
+    @property
+    def relationships(self) -> list[MISPRelationship]:
+        return self.Relationship
+
+    def add_note(self, note: str, language: str | None = None, **kwargs) -> MISPNote:  # type: ignore[no-untyped-def]
+        the_note = MISPNote()
+        the_note.from_dict(note=note, language=language,
+                           object_uuid=self.uuid, object_type=self.classObjectType,
+                           **kwargs)
+        self.notes.append(the_note)
+        self.edited = True
+        return the_note
+
+    def add_opinion(self, opinion: int, comment: str | None = None, **kwargs) -> MISPNote:  # type: ignore[no-untyped-def]
+        the_opinion = MISPOpinion()
+        the_opinion.from_dict(opinion=opinion, comment=comment,
+                              object_uuid=self.uuid, object_type=self.classObjectType,
+                              **kwargs)
+        self.opinions.append(the_opinion)
+        self.edited = True
+        return the_opinion
+
+    def add_relationship(self, related_object_type: AbstractMISP | str, related_object_uuid: str | None, relationship_type: str, **kwargs) -> MISPNote:  # type: ignore[no-untyped-def]
+        the_relationship = MISPRelationship()
+        the_relationship.from_dict(related_object_type=related_object_type, related_object_uuid=related_object_uuid,
+                                   relationship_type=relationship_type,
+                                   object_uuid=self.uuid, object_type=self.classObjectType,
+                                   **kwargs)
+        self.relationships.append(the_relationship)
+        self.edited = True
+        return the_relationship
+
 try:
     from dateutil.parser import parse
 except ImportError:
@@ -226,11 +278,13 @@ class MISPSighting(AbstractMISP):
         return f'<{self.__class__.__name__}(NotInitialized)'
 
 
-class MISPAttribute(AbstractMISP):
+class MISPAttribute(AnalystDataBehaviorMixin):
     _fields_for_feed: set[str] = {'uuid', 'value', 'category', 'type', 'comment', 'data',
                                   'deleted', 'timestamp', 'to_ids', 'disable_correlation',
                                   'first_seen', 'last_seen'}
 
+    classObjectType = 'Attribute'
+
     def __init__(self, describe_types: dict[str, Any] | None = None, strict: bool = False):
         """Represents an Attribute
 
@@ -666,12 +720,14 @@ class MISPObjectReference(AbstractMISP):
         return f'<{self.__class__.__name__}(NotInitialized)'
 
 
-class MISPObject(AbstractMISP):
+class MISPObject(AnalystDataBehaviorMixin):
 
     _fields_for_feed: set[str] = {'name', 'meta-category', 'description', 'template_uuid',
                                   'template_version', 'uuid', 'timestamp', 'comment',
                                   'first_seen', 'last_seen', 'deleted'}
 
+    classObjectType = 'Object'
+
     def __init__(self, name: str, strict: bool = False, standalone: bool = True,  # type: ignore[no-untyped-def]
                  default_attributes_parameters: dict[str, Any] = {}, **kwargs) -> None:
         ''' Master class representing a generic MISP object
@@ -1063,9 +1119,10 @@ class MISPObject(AbstractMISP):
         return f'<{self.__class__.__name__}(NotInitialized)'
 
 
-class MISPEventReport(AbstractMISP):
+class MISPEventReport(AnalystDataBehaviorMixin):
 
     _fields_for_feed: set[str] = {'uuid', 'name', 'content', 'timestamp', 'deleted'}
+    classObjectType = 'EventReport'
 
     timestamp: float | int | datetime
 
@@ -1451,11 +1508,13 @@ class MISPGalaxy(AbstractMISP):
         return f'<{self.__class__.__name__}(NotInitialized)'
 
 
-class MISPEvent(AbstractMISP):
+class MISPEvent(AnalystDataBehaviorMixin):
 
     _fields_for_feed: set[str] = {'uuid', 'info', 'threat_level_id', 'analysis', 'timestamp',
                                   'publish_timestamp', 'published', 'date', 'extends_uuid'}
 
+    classObjectType = 'Event'
+
     def __init__(self, describe_types: dict[str, Any] | None = None, strict_validation: bool = False, **kwargs) -> None:  # type: ignore[no-untyped-def]
         super().__init__(**kwargs)
         self.__schema_file = 'schema.json' if strict_validation else 'schema-lax.json'
@@ -2318,3 +2377,199 @@ class MISPDecayingModel(AbstractMISP):
 
     def __repr__(self) -> str:
         return f'<{self.__class__.__name__}(uuid={self.uuid})>'
+
+
+class MISPAnalystData(AbstractMISP):
+
+    _fields_for_feed: set[str] = {'uuid', 'object_uuid', 'object_type', 'authors',
+                                  'created', 'distribution', 'sharing_group_id', }
+
+    valid_object_type = {'Attribute', 'Event', 'EventReport', 'GalaxyCluster', 'Galaxy',
+                         'Object', 'Note', 'Opinion', 'Relationship', 'Organisation',
+                         'SharingGroup'}
+
+    @property
+    def org(self) -> MISPOrganisation:
+        return self.Org
+
+    @property
+    def orgc(self) -> MISPOrganisation:
+        return self.Orgc
+
+    @orgc.setter
+    def orgc(self, orgc: MISPOrganisation) -> None:
+        if isinstance(orgc, MISPOrganisation):
+            self.Orgc = orgc
+        else:
+            raise PyMISPError('Orgc must be of type MISPOrganisation.')
+
+    def __new__(cls, *args, **kwargs):
+        if cls is MISPAnalystData:
+            raise TypeError(f"only children of '{cls.__name__}' may be instantiated")
+        return object.__new__(cls)
+
+    def __init__(self, **kwargs: dict[str, Any]) -> None:
+        super().__init__(**kwargs)
+        self.uuid = str(uuid.uuid4())
+        self.object_uuid: str
+        self.object_type: str
+        self.authors: str
+        self.created: float | int | datetime
+        self.modified: float | int | datetime
+        self.SharingGroup: MISPSharingGroup
+
+    def from_dict(self, **kwargs) -> None:  # type: ignore[no-untyped-def]
+        if 'Note' in kwargs:
+            kwargs = kwargs['Note']
+
+        self.distribution = kwargs.pop('distribution', None)
+        if self.distribution is not None:
+            self.distribution = int(self.distribution)
+            if self.distribution not in [0, 1, 2, 3, 4, 5]:
+                raise NewAnalystDataError(f'{self.distribution} is invalid, the distribution has to be in 0, 1, 2, 3, 4, 5')
+
+        if kwargs.get('sharing_group_id'):
+            self.sharing_group_id = int(kwargs.pop('sharing_group_id'))
+
+        if self.distribution == 4:
+            # The distribution is set to sharing group, a sharing_group_id is required.
+            if not hasattr(self, 'sharing_group_id'):
+                raise NewAnalystDataError('If the distribution is set to sharing group, a sharing group ID is required.')
+            elif not self.sharing_group_id:
+                # Cannot be None or 0 either.
+                raise NewAnalystDataError(f'If the distribution is set to sharing group, a sharing group ID is required (cannot be {self.sharing_group_id}).')
+
+        self.object_uuid = kwargs.pop('object_uuid', None)
+        if self.object_uuid is None:
+            raise NewAnalystDataError('The UUID for which this note is attached is required.')
+        self.object_type = kwargs.pop('object_type', None)
+        if self.object_type is None:
+            raise NewAnalystDataError('The element type for which this note is attached is required.')
+        if self.object_type not in self.valid_object_type:
+            raise NewAnalystDataError('The element type is not a valid type. Actual: {self.object_type}.')
+
+        if kwargs.get('id'):
+            self.id = int(kwargs.pop('id'))
+        if kwargs.get('created'):
+            ts = kwargs.pop('created')
+            if isinstance(ts, datetime):
+                self.created = ts
+            else:
+                self.created = datetime.fromtimestamp(int(ts), timezone.utc)
+        if kwargs.get('modified'):
+            ts = kwargs.pop('modified')
+            if isinstance(ts, datetime):
+                self.modified = ts
+            else:
+                self.modified = datetime.fromtimestamp(int(ts), timezone.utc)
+
+        if kwargs.get('Org'):
+            self.Org = MISPOrganisation()
+            self.Org.from_dict(**kwargs.pop('Org'))
+        if kwargs.get('Orgc'):
+            self.Orgc = MISPOrganisation()
+            self.Orgc.from_dict(**kwargs.pop('Orgc'))
+        if kwargs.get('SharingGroup'):
+            self.SharingGroup = MISPSharingGroup()
+            self.SharingGroup.from_dict(**kwargs.pop('SharingGroup'))
+
+        super().from_dict(**kwargs)
+
+    def _set_default(self) -> None:
+        if not hasattr(self, 'created'):
+            self.created = datetime.timestamp(datetime.now())
+        if not hasattr(self, 'modified'):
+            self.modified = self.created
+
+
+class MISPNote(AnalystDataBehaviorMixin, MISPAnalystData):
+
+    _fields_for_feed: set[str] = MISPAnalystData._fields_for_feed.union({'note', 'language'})
+
+    classObjectType = 'Note'
+
+    def __init__(self, **kwargs: dict[str, Any]) -> None:
+        self.note: str
+        self.language: str
+        super().__init__(**kwargs)
+
+    def from_dict(self, **kwargs) -> None:  # type: ignore[no-untyped-def]
+        self.note = kwargs.pop('note', None)
+        if self.note is None:
+            raise NewNoteError('The text note of the note is required.')
+
+        super().from_dict(**kwargs)
+
+    def __repr__(self) -> str:
+        if hasattr(self, 'note'):
+            return '<{self.__class__.__name__}(note={self.note})'.format(self=self)
+        return f'<{self.__class__.__name__}(NotInitialized)'
+
+
+class MISPOpinion(AnalystDataBehaviorMixin, MISPAnalystData):
+
+    _fields_for_feed: set[str] = MISPAnalystData._fields_for_feed.union({'opinion', 'comment'})
+
+    classObjectType = 'Opinion'
+
+    def __init__(self, **kwargs: dict[str, Any]) -> None:
+        self.opinion: int
+        self.comment: str
+        super().__init__(**kwargs)
+
+    def from_dict(self, **kwargs) -> None:  # type: ignore[no-untyped-def]
+        self.opinion = kwargs.pop('opinion', None)
+        if self.opinion is not None:
+            self.opinion = int(self.opinion)
+            if not (0 <= self.opinion <= 100):
+                raise NewOpinionError('The opinion value must be between 0 and 100 included.')
+        else:
+            raise NewOpinionError('The opinion value is required.')
+
+        self.comment = kwargs.pop('comment', None)
+        if self.comment is None:
+            raise NewOpinionError('The text comment is required.')
+
+        return super().from_dict(**kwargs)
+
+    def __repr__(self) -> str:
+        if hasattr(self, 'opinion'):
+            return '<{self.__class__.__name__}([opinion={self.opinion}] comment={self.comment})'.format(self=self)
+        return f'<{self.__class__.__name__}(NotInitialized)'
+
+
+class MISPRelationship(AnalystDataBehaviorMixin, MISPAnalystData):
+
+    _fields_for_feed: set[str] = MISPAnalystData._fields_for_feed.union({'related_object_uuid', 'related_object_type', 'relationship_type'})
+
+    classObjectType = 'Relationship'
+
+    def __init__(self, **kwargs: dict[str, Any]) -> None:
+        self.related_object_uuid: str
+        self.related_object_type: str
+        self.relationship_type: str
+        super().__init__(**kwargs)
+
+    def from_dict(self, **kwargs) -> None:  # type: ignore[no-untyped-def]
+
+        self.related_object_type = kwargs.pop('related_object_type', None)
+        if self.related_object_type is None:
+            raise NewRelationshipError('The target object type for this relationship is required.')
+
+        self.related_object_uuid = kwargs.pop('related_object_uuid', None)
+        if self.related_object_uuid is None:
+            if not isinstance(self.related_object_type, AbstractMISP):
+                raise NewRelationshipError('The target UUID for this relationship is required.')
+            else:
+                self.related_object_uuid = self.related_object_type.uuid
+                self.related_object_type = self.related_object_type.classObjectType
+
+        if self.related_object_type not in self.valid_object_type:
+            raise NewAnalystDataError(f'The target object type is not a valid type. Actual: {self.related_object_type}.')
+
+        return super().from_dict(**kwargs)
+
+    def __repr__(self) -> str:
+        if hasattr(self, 'related_object_uuid') and hasattr(self, 'object_uuid'):
+            return '<{self.__class__.__name__}(object_uuid={self.object_uuid}, related_object_type={self.related_object_type}, related_object_uuid={self.related_object_uuid}, relationship_type={self.relationship_type})'.format(self=self)
+        return f'<{self.__class__.__name__}(NotInitialized)'