Kumonga

Shadow Beast Form (影のビーストフォーム, Kage no bīsutofōmu) is form used by Jinchūriki's that possess a seijaku within and is able to go into full shadow beast form or can utilize stages of this ability entirely. They exhibit extraordinary powers due to the immense chakra reserves they possess.

Ability & Usage
a Jinchūriki who possess the seijaku they must undergo intense and gruesome training to fully control its immense power unlike they would with tailed beast they must embrace the beast inside them and combine the will and chakra with their jailer which would give the host extreme boost in speed, agility, endurance and increased strength that would rival a Jinchūriki's who possess tailed beast properties even in stage two form that could give a Jinchūriki an edge against their enemy. each Jinchūriki who possess a seijaku can unlock this form if they trained hard enough but sometimes inexperience Jinchūriki would go on a rampage and wreck havoc with stage one chakra cloak protecting their bodies and enables to access huge amount of chakra that could kill them if any further use of it but can be countered by any seal the caster who place the seal on them.

full access to this form allows them to go full shadow beast mode. this form allows them to fully access the techniques their beast possess and enables them to fight on par against tailed beast and other titanic beings much like fellow seijaku's or susanoo's.