gosh I kinda want to go on a giant worldbuilding / self-lore posting spree right now

yes, the laws of conservation of energy and mass exist in Kaito's world

yes, Kaito's quasi-shapeshifting do not respect them and, in fact, actively defy them

the laws are just a trait of how the "world" is programmed and Kaito is under no obligation to respect them when they're essentially injecting their own code/data into the system

time travel exists in Kaito's world but it's useless for all the things you'd probably want to use it for

you could, in theory, load a backup of the entire world into a separate instance of the world's "program" and explore it

but not only can you not guarantee that the actions that occurred in that sub-world after you started running it were identical to what happened in the "canonical" version of events

you also obviously can't make any changes that would propagate