The Death Sound is Called a Event Object, It is something like play an effect/sound/footprint at a specific frame that's why you have death sound, or attack sound, or foot print, or blood when unit dies, (Also the Dissipate sound and sometimes the walking stomping sound)
To remove it, you just find the death sound among the event object
in Node Editor (Camera Icon)
To remove it, you just find the death sound among the event object
in Node Editor (Camera Icon)