In adapting a work, one sometimes finds there are too many characters to fit on the screen, and some roles can be conveniently squeezed into a single character. Thus the Sidekick, Plucky Comic Relief, and Love Interest might all be the same person. This is the Composite Character.
More rarely, a creator might choose to break a character apart and spread it over several different characters. In this way, you might end up with several characters who are composites of their previous role with a bit of the decomposed character's role. Alternatively, you could simply end up with two characters, each of whom has parts of the old.
This isn't Literal Split Personality. That's when one character is split into two within the show itself.
This is an example. That is also that example.
The game Kimikiss featured a main protagonist named Kouichi Aihara; this was split into two distinct protagonists for the anime: Kouichi Sanada (he gained his appearance) and Kazuki Aihara (he gained his soccer skills).
William Stryker becomes two characters in the Ultimate X-Men. William Sr is an anti-mutant military leader, as in the second X-Men film, while William Jr is the religious extremist from the original comics who later becomes Ultimate Universe Master Mold; gigantic Sentinel.
Apollo Thirteen composited a whole team of astronauts and engineers working to figure out how to power up the command module again into Ken Mattingly and a couple of other guys. Inversely, the team of engineers who figured how to make the Command Module's air filters fit the (incompatible) slots of the Lunar Module were a decomposition of a single engineer who devised the solution while driving to work.
The conversion of Gingaman to Lost Galaxy. The Big Bad Captain Zahab was split off into Scorpius and his more direct counterpart, Captain Mutiny.
And then there's borderline example Furio: He has the costume of Dr. Hinelar's final form, but Sanbash's role in the story. Sanbash's costume, not available at the time, was later used for a new character named Villamax.
Twice when converting Timeranger to Time Force. The costume of Big Bad Don Dolnero was used for comic relief character Gluto, and the Big Bad with some of Dolnero's role was original-design Ransik. Meanwhile, the Rangers' commanding officer Captain Ryuya was split into Captain Logan and, more directly, Alex.
In Kamen Rider Ryuki, we have Kit as Dragon Knight (aka Ryuki, Shinji's shiny suit) until his disloyal alternate self takes over after his Disney Death. After his return, Kit becomes Onyx (aka Ryuga, evil alternate Shinji's shiny suit.) However, we first saw Onyx in a dream of Kit's involving him taking Xaviax's lure. This means Dragon Knight is a composite of Ryuki and Ryuga, but Onyx is splitting Ryuga into two guys. So this is a composite and decomposed character.
On Arrow the comic character of Deathstroke, an Anti-Villain with occasional touches of Anti-Hero, has been decomposed into two characters in the island flashbacks. His name, Slade Wilson, and better fighting ability goes to an Anti-Hero mentor to Oliver. His mask and villainous nature, with slightly lesser fighting prowess goes to Billy Wintergreen, Slade's butler in the comics and here his former partner.
Worf received his status as a very strong alien and being torn between his two heritages (Vulcan and human for Spock, Klingon and human for Worf).
William Riker got his position as First Officer and friendship with The Captain.
Deanna Troi got his limited telepathic abilities and his status of being a Human/alien hybrid. (She was not torn between two heritages: Humans and Betazoids tended to get along quite well together.)
From the video production of Cats; on stage, the character of Gus is usually depicted as a young cat but becomes an older cat for his big number. This number usually segues into another number with the younger version, "Growltiger's Last Stand". The older version was played by Sir John Mills, who was far too old, and blind, to do the required singing and dancing. So, they split both versions into two characters, with the younger Gus now named Asparagus.
Disney decomposed Frollo in The Hunchback of Notre Dame. In the book, Archdeacon Claude Frollo is a tragic Anti-Villain. In the Disney film, the Archdeacon is a sympathetic character while Frollo is a separate character and outright evil.
Young Justice gives us Roy Harper. The one we know turns out to be a clone of the original, who was abducted before the show even began. Eventually the original is recovered and the two wind up splitting elements of Roy from the comic: the clone keeps the name Red Arrow and has a relationship and child with Cheshire, while the original lost his arm and takes the name Arsenal.
Played straight maybe, in Transformers Animated; we're not quite sure what happened with Skywarp and Cyclonus. In Transformers Generation 1, Cyclonus may or may not be an upgraded Skywarp (blame error-prone animation for a confusing Transformation Sequence.) The Animated version, however? Skywarp is one of several clones of Starscream, each with one trait of the original taken Up to Eleven. Skywarp represents his cowardice. As for Cyclonus, he's a brief cameo, but All There In The Manual tells us that his "internal chronometer" is way off, he is seeking someone named Galvatron (that's Megatron's upgraded form in G1 and several other series), and he has some circuitry in common with Starscream, particularly his (now disabled) self-preservation instinct. This hints without saying that Cyclonus is from the future and used to be Skywarp.
Five hats means that five tropers think it is ready to publish.
You are saying that you think this draft is ready to be published. That means the description is not ambiguous,
it doesn't duplicate an existing trope, there are at least three examples, and the title makes sense.
Is that what you meant to do?
You are saying this draft has a ready-to-publish hat it does not deserve and you are taking it back.