to explain the reason the titan blood was there, think about it. The old shack was where the original portal lead to and we learned that the original portal was made by philip so of course it makes sense that the portal door would probably lead to HIS old house. Who else lived in that house? his brother Caleb who after meeting a real witch, secretly passed notes and codes back and forth to communicate so they could meet as was explained during the hayride tour. The code they found to find the titan blood was hidden under the floorboards of Philip and Calebs old house. The map was placed there to allow Caleb to find a secret reserve stash of titan's blood so he could see his "hot witch girlfriend". Thats why there was titan blood there. It was purposely placed there ahead of time by Evelyn so Caleb could travel to the demon realm with her. Also the titan blood vial had an owl stopper which hints that maybe Evalyn was a Clawthorn ancestor. After all Evalyn has the same naming structure as Edalyn and Eda's mother Gwendalyn.