Where does “Шайтан” come from?

Шайтан (Russian) comes from Arabic شَيْطَان, from Arabic شَيَّطَ — to singe; to scorch.

Ancestry of “Шайтан”, step by step

Step	Language	Word	Meaning
1	Arabic	شَيْطَان	Shaitan, Satan; Satan, devil; satan, devil
2	Arabic	شَيَّطَ	to singe; to scorch

Шайтан — Etymology, Origin & Word History | Etymology Explorer