Adaptive Heroes are capable of adaptation - usually instantly (or at the least extremely rapidly) - these types of heroes are often extremely formidable as a result and capable of taking on even the most hard-hitting of supervillain / action villain archetypes.
A common trait of the Adaptive Hero is that they will evolve to become increasingly resilient to whatever may of harmed them in the past as well as gain new powers, abilities and sometimes even entirely new forms designed to improve upon their original flaws.
As a result of this and other traits, due to their Character Development, many Adaptive Heroes are considered effectively invincible as they can almost never truly be defeated, merely contained or exiled.
The most extreme examples of an Adaptive Hero (as well as the most iconic) are RoboCop from the RoboCop franchise, Kenshiro from Hokuto no Ken/Fist of the North Star and Kratos from God of War.
Other examples of Adaptive Heroes are those that they use effective methods and strategies (e.g. discerning the weakness of their enemies and use it to their advantage) as they fight. Best examples for this are Levi Ackerman, who has shown a profound ability to quickly analyze situations, and make calculated decisions in the heat of conflict, Hayato Furinji, who embraces his power of martial arts to defeat the strongest of his foes, the Iron Giant, who appears to be emotionless albeit gentle, but he is in fact an unstoppable killing machine, when pushed too far during the climax of the movie, and Erza Scarlet has the best strategy for her use of powerful magic spells during showdowns she is participating in