But why? What was the logic and reason behind taking multiple attacks to kill something of no threat? For that matter why did he take multiple attacks of opportunity to charge at me just because I was the first person to hit, and do a whopping 2 damage. My max by the way.
I told him I wasn’t upset. I just wanted to hear his logic. The creature had to have some logical thought process for doing the things he did, but I cant get the DM to answer what that is. And this isn’t a new thing. In ¾ of the battles this monsters seem to act in ways that don’t follow any sense of logic whatsoever.
Why cant anyone give me the “why” to anything?
Vrocks are vicious fighters who like to fly down into the enemy and cause as much damage as possible. They prance about in battle, taking briefly to the air and bringing their clawed feet into play. Despite their advantage in mobility, the vrocks’ deep love of battle frequently leads them into melee combats against heavy odds.
In which cases surely it would go for the spell caster first as it can bypass DR.
Anyway, the Vrock takes attacks of opportunity from everyone on him so that he can coup de grace me. The second time he took multiple attack of opportunity just to slaughter the guy who could only do 1 or 2 points of damage, if he was lucky.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.