It's sensible that a creature's AC is equal to their constitution score, and a rather nifty, if perhaps a bit imbalanced in making constitution an even more important stat. If it was 12 or 15 + con modifier it might be more balanced.<br/><br/>I find it a little bit weird that you haven't added any actions to forcefully free yourself from a stomach, either by acrobatics or athletics, even if you technically can't mechanically with 5e's rules on monster that have the devour whole actions. To me, it doesn't make much sense that you can't just use a pair of daggers as ice picks and climb back out of a giant beast, if you are strong or dexterous enough. Still, you are the DM, so play it as you want.<br/><br/>I never really cared for 5e's rule that a creature two size categories smaller than another can't grapple it, even if he/she had ropes or lassos to assist in the grapple. It's not like a god couldn't grapple and hogtie a kraken if that's what he/she wanted to do! Sure, it should be much more difficult, but just making it impossible is lazy gamedesign. But again, it's your game, so this is just my humble opinion.<br/><br/>The first thing that struck me as really odd while reading the VSRD was how ingested creatures take psychic damage, not acid and bludgeoning! What's the reasoning behind that?<img alt=":o" src="./images/smilies/icon_surprised.gif" title="Surprised"/><br/><br/>I love the feats you bundled together by the way, they actually look very viable, atleast in a class with many ability score increases! In fact, they might just be too strong, but I suppose it balances out with the inherent penalties of using vore in combat scenarios.<br/><br/>Other than that, you might want to add a prefix on how heavy slashing weapons can't be used in cutting your way out of a humanoid sized gut. You don't really have space to move a greatsword or glaive around enough to cut anything! Otherwise, it might still be far too easy to upset a stomach with just one attack, as most characters can easily do more than 1/10 their health in damage each round!