Chimail Convergence

Chimail Convergence ( 接収義・怪獣融合(キメイル・コンバージェンス), Kimeiru Konbājensu lit. Confiscation Art: Monster Fusion) is a Take Over spell that is one of the three Take Over Finalizers- forbidden spells that can change the flow of battle for the magician. Chimail Convergence allows the user to combine two or more of their Take Over forms to form a newer, more powerful one.

Description
Chimail Convergence is, well, while it could be summed up as fusion, the reality of the matter is a bit more complicated. It is considered a perversion of the ordinary Take Over by several purists, though it would perhaps be better to describe it as an advancement, taking the utility of Take Over to greater heights. Chimail Convergence is a special Take Over spell that enables the user to combine two or more of the forms of their Take Over Soul—and thus, a new way of combat. When performing the Chimail Convergence, the user shrouds the Take Over forms in their Magic Origin in their magical energy, before using it to break down the physical matter that the beasts are composed of temporarily and merging the eternano particles that the beasts' corporal forms are made out when stored inside, merging all contracts into a single, great one, resulting in a new form.

This results in a chimerical mish-mash of the forms, with complete attributes in the final product all the way down to the appearance. This fusion does allow for advanced transformation states such as OverAssault Mode to be accessed even after the fusion, though if the user merges forms in the Take Over's Exceed Mode, it will cause effects from draining magical power significantly moreso than both of the forms individually, or the user will be unable to transform back into human form once they activate the form. Barring any extreme environmental circumstances with properties magically or otherwise capable of dissolving the fusion, merged forms are forced to stay together forever and will never be able to break apart.

In any case, in addition to appearance, the new form possesses all of the original forms' magic with enhanced speed, strength, and durability, as well as augmented spells that take upon a mixture of the effects of both forms. But, in addition to this, the new form also gains access to completely new abilities which are generally related to the form and its concepts; such as new magic, expansions of old magic, added powers from the form's new appearance and the like. Overall, Chimail Convergence allows the user of Take Over to take their greatest strengths and birth an even more unfathomable power from it.

Trivia

 * This ability was inspired by DNA Digivolution from Digimon, along with a whole lot of other fusion based stuff.
 * "Chimail" is a combination of the words "Chimera" and "Mail".