Daroach my MAN!!!!! AAAAAAAAAAA
Headcanon A (realistic): See this fancy man? See his charisma and fancy aura? Well it is an aura of LIES. This man does a very good impression of being a smooth-talker who has only ever known the good life, but at the end of the day he's a hoodlum from the streets through and through and when it's just him with his crew he fails to have even a lick of decorum in him, and often is causing more trouble than the squeakers themselves ever could. After all, what's the point of stealing your way into the good life if you aren't going to enjoy it as carelessly as you want?
Headcanon B (while it may not be realistic it is hilarious): This probably counts as both realistic AND hilarious, but he cannot say no to his squeakers. If he's in his office to greet someone, in his full business persona, and the door is left open and squeakers get in… Then he is doing business absolutely covered in squeakers without batting an eyelash. In his lap, tucked in the collar of his coat, on and under his hat… They climb all over him and he lets them for the most part, only intervening if they interfere with his ability to stay engaged in the topic at hand, such as sitting on his face or trying to play with his ears. As a result of this rather jarring interruption it causes, squeakers are not allowed in his office, full stop, because once they're in there he can't bring himself to stop the mischief they get up to even when it disrupts negotiations. However, this does have the side effect of him being the most prepared for Kirby’s jungle gym antics, not even remotely fazed the first time it happens, much to the other allies’s surprise, since most of them had to adjust to the concept. (Marx and Bandee being possibly the only exceptions to this, Marx because he just is used to kids goofing off with him and Bandee because they're childhood friends with Kirby, they know all about his need to get everywhere.)
Headcanon C (heart-crushing and awful, but fun to inflict on friends): Daroach used to have a tail, long and thin like you'd expect from any mouse. It came in handy often as an extra limb, relatively prehensile, just enough to trip people up with or to use for leverage. But when he was a young teen, before he became the leader of the spacefaring group he commands in the present day, he got caught stealing in a rather nasty town on a rather unforgiving planet, and the punishment cost him his tail. He still often has phantom pains and nightmares about it, but Dreamland is a welcome relief for him because while the fountain of dreams doesn't entirely stop nightmares for him, it cuts them down a drastic amount and gives him some peace.
Headcanon D (unrealistic, but I will disregard canon about it because I reject canon reality and substitute my own.): He is actually a cane-user and suffers from chronic pain struggles! Being on the run and building your way up to being a master thief is a hard life to live, and the strain has begun to wear down his body prematurely, along with any injuries from various scrapes. However, being a master thief and head of a gang such as his also means little luxury to let this fact be well-known about him, and he continues to lead treasure hunts or even goes out on burglary missions solo to maintain the facade that he’s just as spry as always. It costs him a lot of stamina and he often pushes himself past his limits (to the chagrin of his crew) but his pride and stubbornness refuses to let the pain win out unfortunately. However, post-KSA he finally finds a reason to slow down, do something at a pace much better suited to his physical limits…