istem

/istem/

Cases

SingularPluralWhen to use it
nominativeistemthe desireistemlethe desiresthe plain dictionary form — the doer of the sentence
genitiveistemnithe desire'sistemlenithe desires'the owner — whose it is
accusativeistemnithe desire (as the object)istemlenithe desires (as the object)a specific, known object — whom or what
dativeistemgeto the desireistemlegeto the desiresdirection or recipient — to where, to whom
locativeistemdeat / in the desireistemledeat / in the desireswhere it is; also having — mende bar, "I have it"
ablativeistemdenfrom the desireistemledenfrom the desireswhere it comes from; also "than" when comparing
When to use each case
nominative
the plain dictionary form — the doer of the sentence
genitive
the owner — whose it is
accusative
a specific, known object — whom or what
dative
direction or recipient — to where, to whom
locative
where it is; also having — mende bar, "I have it"
ablative
where it comes from; also "than" when comparing

The endings are the same ones the pronouns wear — that page explains when each case is used.

With an owner

One ownedSeveral owned
myistemimmy desireistemlerimmy desires
youristemingyour desireistemleringyour desires
his / heristemihis / her desireistemlerihis / her desires
ouristemibizour desireistemleribizour desires
you all'sistemigizyou all's desireistemlerigizyou all's desires
theiristemleritheir desireistemleritheir desires

The overlap in the last rows is real, not a mistake: istemleri can mean "his / her desires", "their desire", or "their desires" — context decides.