It seems Oden pulled a Zoro vs Pica on the poor mountain god. Anyway if it is true that the mountain god boar took Tsuru then it is almost a copy paste from princess Mononoke (or from the same source anyway). An homage to Myazaki in OP, beautiful.
We have this huge white boar who is a mountain god (exactly like in Mononoke, the boar is just way smaller compared to this one) who attacks the humans because they took his offspring (in Mononoke the white boar leads his boar army to kill the humans who invaded and damaged the forest of the forest spirit), when the white boar in Mononoke is about to die he is infected by his evil side (let's put it this way) and traps Mononoke who is later freed by the male protagonist (and this could be Tsuru with Kinemon or maybe Oden if he is the one to free her).