The fourth and final Tritanian eeveelution is finally here representing the final new type, Ancient. I feel these four eeveelutions where a great way to introduce Tritania's handful of new types and I hope each has given you a good introduction to all four's themes and vibes.
Pokédex: Arguably the most elusive and mysterious evolution Eevee has Hadeon is different from most other ancient type pokémon in that it represents something much, MUCH... older. Floating whilst coiled around super-heated molten orbs not dissimilar to freshly formed planets they have no mouth to communicate and piercing eyes to overlook the safety of the orb. While they can be a bit hard to raise due to their esoteric and almost alien nature once fully trusting in their trainer they can unleash the primeval wrath of creation to defeat even the most fierce foes.
Misc Notes.
Evolves from Eevee when leveled up while holding an Eldritch Artifact and knowing an ancient type move, only at night.
Design and name are direct references to the Hadean era, Earth's earliest period of history in it's celestial infancy.
Also has motifs of angelic or celestial gods.
Ability: Wrath of Aeons. Hidden Ability: Originate.
Wrath of Aeons: Summons Primeval Storm an ancient type weather effect for 5 turns on entry.
Originate: Upon entering battle warp reality as such the game's rules, logic, balance and mechanics reflect generation 1 (bugs and all.) Any type non-existent in generation 1 becomes normal.
Base Stats.
HP:200
Attack:20
Defense:80
Sp.Attack:90
Sp.Defense:80
Speed:55