Cases and clipping, ho!
A recount:
-Cases:

Nominative

Accusative

Reflexive

Genitive

Dative

Vocative

Instrumental

Locative

Intrative

Inessive

Subessive

Ablative

Allative

Delative

Elative

Illative

Sublative

Perlative

Prosecutive-Vialis

Antessive

Abessive

Revertive

Identical

Ornative

Adventive

Possessive

Partitive

Anessive
-Classes:

Regular

"Clipping"
-------------------------------------------------------------------------------------------------
Let's start with the basic cases:

Cases:
- Nominative
- Accusative
- Reflexive
- Dative
- Vocative
- Instrumental
- Locative
These seven make up the core cases used in the Ktarh morphosyntactic alignment. All of these can indicate, in some form or another, the subject, agent and object.
Let's start with the nominative.
The nominative is primarily used to mark the subjects of many intransitive verbs and agents of many transitive verbs. That's its primary use; the secondary use is to mark inalienable possessions and, rarely, company (that is, it can function as a commitative and possessed case).
The accusative marks the objects of transitive verbs, but also sometimes the subjects of intransitive verbs (for emphasis, occasional). It's also used to denote the direction towards something else is facing (when stacked with the dative).
The reflexive marks both the agent and object of transitive verbs when both are the same. It marks the verb for the mediopassive voice.
The dative denotes the recipient and beneficiary of verbs that have a higher transitivity than plain transitive. It also marks the subject in generic modal constructions where the attributes expressed are emotions, feelings or sensory inputs. Stacked on the accusative, it marks the direction towards which something is faced.
The vocative has two uses - to call something or somebody, and as a subject/agent of imperatives.
The instrumental has two uses - to denote an instrument with which the action denoted by the verb is performed, and to denote the company in which the agent or subject performs the action denoted by the verb (instrumental and causative). It can also be extended to mark the instrument as a subject (as in, "the axe-INST fells the tree-ACC", coming from "John-NOM fells the tree-ACC with the axe-INST").
The locative has two uses - to mark the location at which some other entity currently is, and to mark the topic of conversation. While it doesn't actually fulfill the role of object, topics marked with the locative prevent an accusative object from appearing.
-------------------------------------------------------------------------------------------------
Now, the spatial cases (and one temporal case), too!

Cases:
- Intrative
- Inessive
- Subessive
- Ablative
- Allative
- Delative
- Elative
- Illative
- Sublative
- Perlative
- Prosecutive-Vialis
- Antessive
The intrative can be used in two ways: when attached to a dual or plural, denotes location between the instances of the marked word, but when several words are marked consecutively, it denotes location between them. The second form requires hyphenation in writing (so that you get <narinadī> (between two children), but <narenēki-hsēkunēki> (between a child and a tailor) ).
The inessive denotes static location inside the modified word. Nothing else.
The subessive denotes static location beneath the modified.
The ablative denotes two things - the first is motion from something, and the second is the object received from something (that's marked in the genitive)
The allative denotes two things - the motion towards and up to the modified word, and motion onto the top or topside of the modified word.
The delative denotes motion from the top of the modified word.
The elative denotes motion from the inside of the modified word.
The illative denotes motion into the modified word.
The sublative denotes motion to beneath the modified word.
The perlative denotes motion through the modified word (into and out of it).
The prosecutive-vialis denotes both the path or way of motion, and method used to acheive a goal (seperate from the instrumental since the instrumental is specific to instruments and tools)
The antessive is the only temporal case of the set, and denotes that the action happens before that which is marked with it.
-------------------------------------------------------------------------------------------------
-Cases:

Genitive

Abessive

Revertive

Identical

Ornative

Adventive

Possessive

Partitive

Anessive
The cases most common to stack, the genitive, abessive, revertive, identical, ornative, adventive, possessive, partitive and anessive, share a few common properties - most importantly, they a) are the most frequent to stack b) share the first two ablaut grades (some share all three).
The genitive is sometimes used to mark the "possessor" of immaterial things (emotions, opinions etc.) or things such as injuries. It can also be used to mark the material of something else, and the place and/or time of origin or occupation (house-NOM winter-GEN - winter home, home occupied during winters/home built during winter).
The abessive's basic use is to denote the lack of something or a state of contradiction. It can be used only when stacked - when stacked with the core cases, it indicates that the action can't be fulfilled due to the lack of the marked; stacked with the genitive and possessive (only in their possessory function), it indicates that, while marked as a possessor, the marked now denotes former possession; stacked with the dative in its benefactory function, it denotes the malefactive. It can also be stacked with the motive cases to generally denote that the motion was supposed to happen but didn't, or the inability to take the marked path; stacked with the prosecutive-vialis denotes that a path other than the marked one was/is/will be used.
The revertive by itself marks location opposite or across an obstacle to that marked (house-REV stands factory-NOM = the factory stands opposite the house/across the street from the house), but when stacked with the possessive, it marks the same thing as a possessed case would. When with a non-singular or multipartite subject (and often with a verb of motion), it can be stacked with the prosecutive-vialis to denote that the subject's parts performed the action from opposite sides of the path (truck-DU-NOM drove road-VIA-REV = the two tracks drove on the opposite sides of the road); it can be extended with any case of motion to denote that the parts went seperate ways.
The identical case can only be used stacked - it is used to denote that the marked have one or more of their attributes very simmilar or identical. It can also be used as a translative case when used with a verb of motion and when used on both the subject and object (or on word marked with both the nominative and identical but doesn't denote a core argument).
The ornative case can only be used when stacked. It's limited in scope, but primarily denotes equipment or supplies (or even manpower) carried along for the performance of action, but there where the commitative cannot be used. It can also be used to denote decoration. To denote the equipment, it must be stacked onto the instrumental, but it also requires that the subject be marked with (in order) the nominative, possessive and ornative. To denote decoration, it must be stacked onto the nominative, but the decorated must also acquire a possessive marking.
The adventive must be stacked with some other case - it denotes that what was marked for the role wasn't what had been planned beforehand (different route than expected, different subject than previously planned).
The possessive basically denotes possessorship where the genitive doesn't (for tangible/material things, then for land (and territorial surface area and volume in general) and intangible goods (such as knowledge) ). Its additional uses are described above with the cases with which it stacks.
The partitive denotes several things - interchangeably with the genitive, it denotes material, but also denotes a segment seperate from the whole (such as a cog from a machine).
The anessive functions a lot like the base use of the abessive, except that, while the abessive marks that the lack of something obstructs performance of action, the anessive denotes that the
presence of something obstructs, instead. It can only be used with the core cases and the prosecutive-vialis (where it denotes the inability to take the path).
-------------------------------------------------------------------------------------------------
Yeah, that's about all of them. If anything needs explanation, ask me.