Devil Fruits

AkumaDevilFruits reads a living entity's Devil Fruit as Mine Mine no Mi keeps it. The details below were read from the base mod's bytecode, version 0.11.5.

if (AkumaDevilFruits.isZoan(player) && AkumaDevilFruits.isMorphed(player)) {
    // a Zoan user, transformed right now
}
AkumaDevilFruits.resetCooldowns(player);

Method	Does
fruit(entity)	the AkumaNoMiItem it ate, if any
hasFruit(entity, id)	whether it ate that fruit, e.g. mineminenomi:hito_hito_no_mi
isZoan(entity)	whether its fruit is a Zoan: plain, ancient, mythical or artificial
isMorphed(entity)	whether it is transformed right now: a Zoan's point, or any other morph
resetCooldowns(entity)	ends the cooldown of every equipped ability (the base mod syncs it) and returns how many were cooling down

Notes:

• The base mod's Zoan points never time out, so there is no morph duration to extend. To strengthen a form, check isMorphed and add modifiers, as Cruise's Rumble does.
• The base mod's mineminenomi:zoan item tag leaves the artificial Zoans out. isZoan counts them.
• The Hito Hito no Mi (Chopper's fruit) is a Zoan with no abilities in 0.11.5, so its user is never morphed.

ExternalMorphs

Since 3.1.0. A morph put on an entity from outside its own abilities - a curse that turns a player into a toy, a fruit that keeps its user a child. A morph normally travels with a morphing ability of the morphed entity; these have none.

ExternalMorphs.set(player, MyMorphs.TOY.get(), true);                   // here and on every client that sees it
ExternalMorphs.keep(MyMorphs.TOY, player -> MyHelper.isToy(player));    // once, at mod construction

What it covers, each a fault of the base mod (0.11.5):

• watchers: sent to the entity and everyone tracking it, and again to a player who starts tracking it later, for the morphs a keeper says still hold;
• duplicates: the devil fruit sync appends the morphs it carries, so a watched entity can hold one twice - taking it off removes every copy;
• size: the last morph off clears the list properly (losing the fruit alone left the player at the morph's size), and the dimensions refresh;
• respawn, dimension change, login: the base mod drops these morphs; with a keeper, the player gets it back if it still holds, and loses it if not.

Both sides need 3.1.0

It is a packet: network protocol 5.

Giving Devil Fruits to NPCs and mobs, and what they do with them: Devil Fruits on NPCs.