Forgotten One
Classic
Expert
Master| Type | Boss – Aquatic |
|---|---|
| Environment | Aquatic Depths |
| AI Type | Forgotten One AI |
| Damage | 80160240 (Contact) 60120180 (Whirlpool) 50100150 (Abyssion Spit) |
| Max Life | 6000084000107100 |
| Defense | 50 |
| KB Resist | 100% |
| Immune to |    |
Classic Expert Master| Type | Boss – Aquatic |
|---|---|
| Environment | Aquatic Depths |
| AI Type | Forgotten One AI |
| Damage | 80160240 (Contact) 60120180 (Whirlpool) 80160240 (Dark Ripple) 70140210 (Abyssal Strike) |
| Max Life | 30000 / 6000055440 / 8400070620 / 107100 |
| Defense | 40 |
| KB Resist | 100% |
| Immune to | |
| Coins |  |
|---|
- Item (Quantity)Rate
- Only one of the following 6 items can drop at a time
- 16.67%
- 16.67%
- 16.67%
- 16.67%
- 16.67%
- 16.67%
- 10%
Greater Healing Potion (5–15)100%- 14.29%
- 10%
“Aye, I once saw a sea demon risin' from those depths. Somethin' dark, somethin' ancient, somethin'... uhh... You gonna buy somethin'?!
The Forgotten One is a Hardmode, post-Plantera boss fought in the Aquatic Depths. The boss has multiple forms, each more powerful than the last.
While The Forgotten One is alive, its exclusive music Beneath the Depths will play.
Spawn
The Forgotten One does not spawn on its own and requires the player to kill Aquatic Hallucinations in the Aquatic Depths. They will drop Abyssal Shadows, which will inflict the False Presence debuff once for every one picked up. Upon reaching three stacks of the debuff, Forgotten One will emerge. Multiple Forgotten Ones cannot be summoned through this process.
After Forgotten One has been defeated in the world at least once, Abyssal Shadows will behave like normal Summoning items, summoning the boss on use.
Behavior
Attacks
- If the player is not in a body of water, it will enrage in a manner similar to Plantera. While enraged, it moves at a higher velocity, summons Abyssal Spawns more often, and its spit projectiles will home in on the player.
- Forgotten One slowly follows the player, attempting to swim into them. It will also periodically fire wall-piercing whirlpool projectiles.
- Immediately at 85% life and occasionally below it, Forgotten One will hide within its shell, causing it to take 1 damage per hit. When in its shell, it will rapidly shoot at the nearest player with fast moving and heavy damaging spit projectiles.
- At 50%/66% life, Forgotten One's shell cracks as it enters its second phase, immediately launching its shell attack and gaining numerous changes.
- Starts periodically shooting pairs of projectiles together; water ripples that bounce along walls, and semi-homing dark magic slashes that attempt to block player movement.
- Forgotten One's shell attack can be used much more frequently, but only reduces damage by roughly 50%. It can also use all of its other regular attacks while in its shell, as well as summoning 5 Abyssal Spawns whenever it enters this attack.
- At 33% life in Expert Mode, Forgotten One transforms into its third phase.
Summons
| Image | Name | Condition |
|---|---|---|
 |
Abyssal Spawn | Below 50%/66% life |
In Expert Mode
Expert Master| Type | Boss – Aquatic |
|---|---|
| Environment | Aquatic Depths |
| AI Type | Forgotten One AI |
| Damage | 160240 (Contact) 120 (Old God's Spit)180 (Old God's Spit) 160 (Abyssal Strike)240 (Abyssal Strike) |
| Max Life | 27720 / 8400035310 / 107000 |
| Defense | 30 |
| KB Resist | 100% |
| Immune to | |
- Item (Quantity)Rate
- Greater Healing Potion (5–15)100%
Treasure Bag(Forgotten One)100%- 100%
- 25%
- 100%
"Forgotten One breaks free of its ancient prison!"
Forgotten One (Released) is the Expert Mode exclusive final phase of the encounter. The transformation is notified with the status message, "Forgotten One breaks free of its ancient prison!"
Behavior
- Movement speed increased by roughly 50%.
- Forgotten One immediately uses its spit attack after entering this phase.
- Forgotten One retains all previous attacks, but with a few changes:
- Spit attack fires more shots and purple shots that deal increased damage, but Forgotten One no longer reduces incoming damage while using the attack.
- Fires three dark magic slashes at once, which are also purple and inflict much higher damage.
Aftermath
- Upon defeating Forgotten One for the first time, the Aquatic Depths biome's Choking Aura debuff will be replaced with the Purified Waters buff, allowing them to breathe water and air in the biome without taking damage. This is indicated with the message upon its defeat "The toxic haze of the depths has been lifted..."
- The Diverman will start selling The Whirlpool.
Trivia
- Forgotten One resembles a large Parapaguridae hermit crab, an aquatic crab that lives in deep water.
History
- 1.7.0.1:
- Buffed maximum life from 50000 / 80000 / 110000 to 60000 / 84000 / 107100 and damage from 60 / 120 / 180 to 80 / 160 / 240.
- Rebalanced defense between phases from 45 / 45 / 40 to 50 / 40 / 30.
- Buffed Whirlpool damage from 50 / 100 / 150 to 60 / 120 / 180.
- Nerfed Abyssion Spit damage from 60 / 120 / 180 to 50 / 100 / 150.
- Nerfed Old God's Spit damage from 160 / 240 to 120 / 180.
- Buffed Dark Ripple damage from 60 / 120 / 180 to 80 / 160 / 240.
- Buffed Abyssal Strike damage from 50 / 100 / 150 to 70 / 140 / 210.
- Buffed stronger Abyssal Strike damage from 120 / 180 to 160 / 240, and it now applies Shadowflame.
- 1.6.5.6: Renamed from "Abyssion, The Forgotten One" to "Forgotten One".
- 1.6.3.8: Now drops R'lyeh's Lost Rod.
- 1.5.1.0: Now drops Whispering armor.
- 1.2.12.1: Introduced.
