Discord-Daq «-'e'» mojaq wIrIchtaHvIS lo'meyDaj vIbuS. qen QIj SuStel 'ej meqqu'mo' ghaH, De'wI'wIjDaq mojaqvam QIjbogh ghItlh'e' vIpol. 'ach DaH SuStel latlhpu' joq vIghelnIS.

mu'tlheghDaq «'oH, ghaH, bIH, chaH» lo'lu'chugh SeSorDaq «-'e'» chelnISlu' net Sov. ghantoH: «Ha'DIbaH 'oH vIghro''e'.» qay'be'. ghellu'chugh jaSHa' chelnISlu'. ghantoH: «nuq 'oH vIghro''e'?» qay'be' je.

'ach reH mu'tlheghmeyvetlhDaq De' ngo'Daq ngam mojaqvam, qar'a'? not De' ngo''e' 'oS ghelbogh mu' («'Iv, nuq»), qar'a'? vaj tlhIngan Hol pabHa' bIvlaw' mu'tlheghvam: «Ha'DIbaH 'oH nuq'e'?»

'ach «Hov leng: maQmIgh» (STID) HaStamuchDaq Qoy'lu': «DevwI' ghaH 'Iv'e'?» ‘Who is the leader?’ — vaj latlh lo' ghaj'a' mojaqvam?

Short version in English:

In be-sentences -'e' marks the subject, which SuStel explained as one of the TOPIC uses of the suffix. Topic means that it marks old information, so I concluded logically that question words like nuq and 'Iv cannot be marked by -'e'. But there is a sentence in STID, «DevwI' ghaH 'Iv'e'?» ‘Who is the leader?’ Is the usage of -'e' in be-sentences a different (fourth) usage that is neither topic, focus, nor head-marking in a relative clause? Or is it perhaps focus just in this one example after all? Or can we dismiss it saying that Uhura's Klingon isn't quite perfect and native-like and she made a mistake here (I believe she said this sentence)?

'Iv and nuq are pronouns that stand in for the answer. If the answer is DevwI' ghaH Qugh'e' Kruge is the leader, then the question of the leader's identity is DevwI' ghaH 'Iv'e'? Don't worry about the required topic marker in the question version; it's just there because it's required in the answer.