Final Fantasy IV (iOS) - Superboss: Geryon (Active/Hard) (No Adamant Armor + Cursed Ring Combo)

Bestiary Entry: #199
Steal: Nothing
HP: 200,000
EXP: 800,000
Gil: 99,999

Stats: Shown at the end of the video
Augments: Show at the end of the video

Abilities
Inferno: Deals massive fire damage to both the enemy and ally. This is Rubicante's special move.
Maelstrom: Brings your entire party down to single digit health, but there's a chance it will miss. This is Barbarricia's special move.
Tsunami: Deals water damage to all enemies, a small chance that it will instantly kill anyone without Ribbons or Adamant Armors. This is Cagnazzo's special move.
Gas: Inflicts numerous amounts of negative effects, easily immuned by Ribbons and Adamant Armors. This is Scarmiglione's speical move.
Cursed Elegy: Practically the same as a MT Slow. Uses it as a counter whenever attacked by any move. This is Scarmiglione's special move in the PSP remake (Don't remember if he also did it in the SNES and GBA).

Notes
I gave myself a slight extra handicap by not wearing any armor on all my heroes except Cecil, which he has the Onion Armor.
"If Tsunami is supposed to instantly kill anyone, then why hasn't your characters without Ribbons not yet dead?"- I actually do not know how Cecil, Kain and Edge immuned the Tsunami's Instant Death without Ribbons or Adamant Armors.
Though Protect Rings would've worked to negate Lightning and Inferno, it's a pain to grind Ahrimans and when trying to find for them, it actually might not be an Ahriman. At least when grinding for Crystal Rings, you are guaranteed to find the enemy who has it, and that is the Red Dragon found in the Lunar Subterrane B8-B10. You can guarantee find Red Dragons in those levels in the Lunar Subterrane if you're using a Siren. Be patient when trying to grind for Crystal Rings, as you might get a Red Fang instead, and these two items can only be stolen from the Red Dragon.
Geryon can hit like a fucking truck, but will hit like a small hammer by Blink, Protect, Brace (Defend is you don't have it) or high evasion.
He's the perfect mob to grind Gil so as to obtain more Sirens because he can be battled infinitely.

Strategy
Only one physical attack would be enough to 2-shot with 99,999 damage. Kain is still my main force of damage with his Jump, Focus, Darkness and Limit Break. Rosa will keep everyone alive with her white magic, remove all the negative effects from Gas with her omnicasted Esuna and will cast Haste on everyone in case Geryon decides to counter with Cursed Elegy. Cecil will tank the physical damage, Rydia and Edge played no part in this even if I made Rydia dualcast Meteors twice.