"Daenero lēkī iksi."

Translation: We are Daenerys's brothers.

[Luis_Domingos]

It's perfectly correct to use just an apostrophe as a possessive in a name ending in -s; "We are Daenerys' brothers" should have been accepted without the typo remark.

[StephieRice]

Technically true, but also quite poor form.

The main reason being pronunciation. In all cases of names that end in "s", you must pronounce the possesive with an extra sound /z/. However in any other word that ends in s, like a plural, you don't pronounce an extra sound.

Examples:

John's. Pronounced as written.

Schools'. Pronounced as written.

James's. Pronounced as written.

James'. Pronounced as James's.

It is still grammatically correct, but as a native English speaker it seems so wrong.

[purplepurpur]

Okay sure, but don't act like English is consistent with its spelling, 'cause it's not.