Originally Posted by Liae
Can anyone think of a way to make this work?
You have to take 1 level of druid, 4 levels of ranger or a level of cleric with the Animal domain.
The feat itself actually has nothing to do with the selection of an animal companion. That is hardcoded into the character generator and level-up process.
Edit: It might be able to create a new custom base class that allows a warlock hybrid to use the animal companion spell OR create a warlock prestige class that does the same, but you're going to have mess around with .2da files for starters. I've done a little exploring with those but nowhere near enough to even begin to tell you how to go about it.