Primeval Currents (じゃぶじゃぶ旧海道 Translated: Old Sea Road) is the 4th sub-chapter of Uncanny Legends, added in version 7.1.
Difficulty in this UL sub-chapter is rising as the stages progress. The first 2 stages are arguably the easiest in the sub-chapter. The sub-chapter's 3rd and 6th are most likely hardest while 4th and 5th shouldn't be too bad.
This sub-chapter introduces one new enemy:
- Othom: Mooth's Relic/Floating variant, with high health, damage and speed, plus a 100% chance to Curse cats for 2 seconds. Notably, it attacks from a range of 340 but hits cats up to 440px away, allowing it to outrange many cats.
This sub-chapter contains 6 stages:
- Stage 4-1: Marine Town - A Metal Hippoe spawns at the beginning of the level. Snache, UltraBaaBaa and Relic Doge are peons, with Gory and General GreGory appearing as periodic threats.
- Stage 4-2: Wandering Conch - Le'noir serves as the boss. Various Zombies appear as peons.
- Stage 4-3: Palcaccio Waters - The battle leads off with four Heavenly Hippoes. Some time after, Gabriels and Mr. Angels start spawning. After attacking the enemy base, a Bore will appear as the main threat, Heavenly Hippoes will spawn every so often and Angelic Gories will spawn constantly. An additional two Bores appear some time later.
- Stage 4-4: Utsubobo Seamount - Just a Kory, an Oldhorn, another Kory, another Oldhorn and a Berserkory, in that order. The only peons, B.B.Bunnies, are spawned occasionally.
- Stage 4-5: Frontier Dawn - Snache and Relic Doge appear as peons. Those Guys are also spammed at the beginning of the level, but eventually stop spawning. Upon damaging the enemy base, THE SLOTH will spawn alongside a trio of Rain D., and another three Rain D. appear after 20 seconds. Sir Rel is spawned occasionally, but will stop after a total of 25 Sir Rels have appeared.
- Stage 4-6: Rutsborg Vortex - Croco and Squire Rel spawn at a mild rate. After 33.3 seconds, Mooth will appear. Once the enemy base's HP has been reduced to 99%, Othom will appear as a boss. Gabriels, Heavenly Hippoes, Angelic Gories, Angelic Sleipnirs, Relic Doges and Sir Rels appear as support.