So I looked through the Internet to find an answer for my small but awesome problem but I have come up empty. So I turn to the good people of the forums!
Here is the story, I'm working on making a new character for a sandbox playthrough which has a lot of monster hunter in it. Monsters ranging from vampires and demons to dragons and giants. My character idea is to have someone that could climb and ride or attack these creatures if they are big enough like in Shadow of Colossus or Monster hunter generations. In Monster hunter the hunter jumps on from a high place and stabs the monster till it bucks him off. Finally my question, how would I go about gearing a character to be able to something as insane and crazy as this. I understand the kaiju rules apply for somethings but what about riding say a dragon after you climb it. The riding rules say you control it once you make a ride check but that doesn't make since if you were just fighting the creature.
TL;DR
Need rules for climbing,holding on to, and striking a creature. + how the Ride check works for mounting an enemy mid-combat.