Yes, KAISERS is a Scrabble word!

Letter values in Scrabble US: K 5, A 1, I 1, S 1, E 1, R 1, S 1.

Is it a valid word?

KAISERS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the title of the Holy Roman Emperors or the emperors of Austria or of Germany until 1918