Realistically, Relics at this point would be obtainable (I imagine) something like this:


Kill 1-3 bosses, get basic relic weapon parts.

Gather 20,000 items from botanist, miner and fishing.

Craft all 20,000 items into a non tradeable key items. (rank 45 synth, all classes)

Talk to NPC, trade base relic item and 20,000 key items to NPC for stage 2 relic.

Kill 50,000 monsters with the stage 2 relic.

Talk to NPC for stage 3 relic.

Trade 500million gil to the NPC with the stage 3 relic to the NPC for the stage 4 and final relic weapon.

I might have gone overboard, but who knows.