Zaladar has two bugs that involve his ability.

#1

Often, when an opponent has no allies in play, yet Zaladar has enough shadow energy for his ability, the option to use his ability on the opponent's hero does not display. Sometimes it does, usually not the first time though. No other effects are out, etc. that should prevent it.

This leads to #2

If you then have 8+ shadow energy on him. He only allows it all used up at once. But.... Only adds extra possible targets... usually only the opponents hero and 2-3 allies. This targeting also then has another glitch. Only allowing you to hit 2 of the targets.
shouldn't you be able to use his ability once (4 energy) then activate separately it again if 4 more energy and so on...