Hello, Anti Paladins take the fiendish boon ability at lvl 5. It comes in two forms:
You either buff up your weapon (like paladins do) or you get a "Fiendish Servant" as per summon monster III (in antithesis to the paladin's holy horse). As you level up summon monster III becomes IV, V and so on.
So my question is, how much do those "servants" serve you? Are they loyal? I mean yeah a fiendish animal could be loyal whatever, but what about a shadow or even worse a succubus. Do they do as they are told no questions asked, do they seek to betray you, are they a gift from the dark god you serve so their job is to serve you at their best of their abilities or are they bound to it and have to obey you while they loath doing so. Are they really there or are just manifestations of the creature just like from the summon monster spell. I'm not even going to ask about the profane gift so many threads about that.
To sum it up.
1. Loyalty and attitude against you.
2. Is the monster the boon or is the ability to summon the monster the boon (fluff wise). (Like, good job reaching level 5 of epic douchiness I reward you with a servant to aid you, please take your pick dont be shy or I reward you with the summon monster III spell from pg 352 from the Core Rulebook, keep up the bad work.
3. Can you summon demons if you serve devils and vice versa (roleplay wise).
4. Is the monster really there or just its manifestation.
I mean, it is a "Boon" and the monster is a "Servant" but these are Demons and Devil we are talking about here... so I'm not sure.