magnit

/maɡnit/

Cases

SingularPluralWhen to use it
nominativemagnitthe magnetmagnitlethe magnetsthe plain dictionary form — the doer of the sentence
genitivemagnitnithe magnet'smagnitlenithe magnets'the owner — whose it is
accusativemagnitnithe magnet (as the object)magnitlenithe magnets (as the object)a specific, known object — whom or what
dativemagnitgeto the magnetmagnitlegeto the magnetsdirection or recipient — to where, to whom
locativemagnitdeat / in the magnetmagnitledeat / in the magnetswhere it is; also having — mende bar, "I have it"
ablativemagnitdenfrom the magnetmagnitledenfrom the magnetswhere 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
mymagnitimmy magnetmagnitlerimmy magnets
yourmagnitingyour magnetmagnitleringyour magnets
his / hermagnitihis / her magnetmagnitlerihis / her magnets
ourmagnitibizour magnetmagnitleribizour magnets
you all'smagnitigizyou all's magnetmagnitlerigizyou all's magnets
theirmagnitleritheir magnetmagnitleritheir magnets

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