For the Selye fight scene you beed to go full out Nauxus route and Lizard tribe and to active the full on thing you need to visit the Bull tribe first when you want to pick sides for joining the war and after the Bull go to the Lizard and talk to Nauxus and accept immediately and that makes your choice to choose one Tribe chief to join in the war on and for you to know you had your full lizard tribe route.... You will need to be invited to the Lizard Tribe's festival just like the bull has and after the war collect every emblem and as time passes visit the waterfall on days 90-99 or 80-89 to fight selye and prepare some MP potions rather than HP cause high MP makes you heal twice than a HP potion..