If anyone is confused how to avoid the insta death laser, go down instead of up. Apparently i'm too stupid to realise it earlier than i did, i kept going to the highest point, the top right corner :p, it's supposed to only be for when it rams
The fire spirit is underground (not the floating jellyfish) - you will know you're close when you see the glowing blocks (and it's near the wyrm hive).
If you continue the alchemist's quests on the magic island, he'll explain how to make new fire gems. If the alchemist isn't at the magic island, you need to complete some quests with him at the starting island before he teleports to the magic island.
The fire spirit is underground (not the floating jellyfish) - you will know you're close when you see the glowing blocks (and it's near the wyrm hive).