The Tower of Ruin is a Level 40 Secret Realm. Although the difficulty is quite high, it's popular among Professionals due to its considerable rewards.
Moreover, this is the only Spatial Secret Realm below Level 50.
As a Space System Secret Realm, the creatures within are rare Space System demons not often seen elsewhere.
Because of the presence of these demons, this Secret Realm can be considered undoubtedly the highest difficulty at the Level 40 tier.
However, this only applies to other Professionals.
For Lin Ye, a Space Mage, this Secret Realm is practically like his own backyard.
Especially since Lin Ye possesses the skill 'Space Manipulation,' which is the key skill for a Space Mage.
Any Space System skill these demons use could potentially be learned directly by Lin Ye, just as Lin Ye previously learned Gao Lanlan's skills.
"According to Sikong Ming's notes, every three years, there appears a group of Dimension Wanderers within this Secret Realm..."
