Tier 6 Spiritual Land!!!
The upgrade conditions were met the moment the Emperor Penguin and more than four other beasts born in the Spiritual Land reached the Transcendent Rank. The upgrades between ranks became easier as Noah first got his hands on an abundant amount of Transcendent and Saint [Core]s during the second run-through of the Devilish Abode, and then received even more condensed cores that had undergone refinement, the Spirit Stones from the Profound Astral Sect.
This, on top of the Medicinal Fruits he unlocked when the Spiritual Land was upgraded to the fifth tier, made for a very quick rise of strength in the beasts. He planted the herbs called [Frozen Angelica] and used the rainbow-colored fruits from the [Regal Flora] in the Time Space while also using one of the very few low ranking skills, the rank S [Budding Farmer], that still held great utility.