@Hakaishin Aro Kappa are kinda forgetful mamono to be honest. And the mist continent mamono (except for Youko and Jiangshi) are kinda underwhelming for me at least.
"No one talks about the giant slug cause they’re out shined by the tritonia"
More like they are not underrated, they are just very bad. Samething for Mandragora for example, they are just not good or particulary appealing or even interesing.