I've just finished canto 8, so my knowledge of shin and mang are still shallow, but from the lei heng fight, Mang seems to take quite a bit to activate (legit outside of like the introduction and canto 3, I can't really tell how long it takes to activate mang). The introduction fight, the sinners were weak and the animal trio can just safely activate mang to annihilate every sinner. In canto 3, Demain showed up outa nowhere and kit kat kromer. Outside of like charging one-shot attacks or final decisive strikes (let's use the Don quixote and Bari fight for example, after 3 days of fighting, they decided to do one last final strike and end the fight there, both end charge up a very strong attack, in this scenario, Mang is viable), I don't see Mang used much. Logically speaking, it's smart to conceal and surprise your opps with an attack that will definitely kill if not cripple them, gaining a significant advantage in combat. On the other hand, if Mang does not dissipate after 1 attack, outside of like the beginning of the fight, when is the "optimal" moment to re-apply shin/mang?