Mine Mine no Mi 0.10.0 #25 (Patreon)
Content
Almost forgot this was supposed to be a boss update with so many random features and updates lately...but alas...bosses are here to stay, and they've got some well needed updates.
First off, their arenas got a nice extra bit of detail via skyboxes:

Something more visually appealing than an empty sky, this can be expanded and at first I wanted to do something like this:

But the illusion breaks when you go near the edge or at certain angles unless you always center the skybox on the player...and...generally speaking people expect ground to stay in place....not move with them...but who knows, this feature is still young.
A lot of work was done for the Baroque Works bosses this month, they're also the most complex ones this update because of their devil fruits.
Mr. 3 got fully added with all of his abilities including this nice "ultimate" ability:

Once the charging starts you can stop it by dealing enough damage to Mr. 3 if you fail and the structure goes up it'll apply arena wide debuffs and damage over time for some time. Obviously Standard mode generates slower than Hard mode, he'll also run slower and generally be easier to cancel during Standard mode. Mr. 3's fight is mostly done, he's got 3 phases including his default one, Candle Champion and the above ultimate phase (named Tokudai Candle) during which he'll get different abilities to match them (also the entire idea of this phase is he kites the players around while damage over time eventually gets them or the ability stops).
Mr. 4 and Miss Merry Christmas (and technically Lassoo but he's mostly used as an offscreen mechanic at the moment) got added (tho still very WIP and without textures), their shtick will be that Miss Merry Christmas will be able to stun you by grabbing your feet and depending on your distance from Mr.4 he'll either smack you for big damage with his bat or throw explosive balls at you.

(don't worry this will 100% be telegraphed as well as her general position underground...this is still extremely WIP)
Overall their fight follows a similarly linear pattern as Mr.5's and Miss Valentine's fight where once you get the hang of it there ain't much to get surprised by, avoid big melee hits, avoid getting caught, kill fast.