This is a mobile-only event that's based around collecting soul stones for the Hero Kai. It's a 3-day event, and there are 4 tasks.

Tasks:
1. Spending Energy (Spending Energy)
100-200-300-500-700-1000-1300-1600-1900-2200-2500-4000-6000-8000

2. Value Exchange (Spending Emeralds)
10-30-50-70-100-250-450-700-1000-1500-2500-4000-7000-14000-22000-32000-40000

3. Assemble (Days Login)
1-2-3

4. Warrior's Becoming (Promote to rank)
Green-Blue-Purple-Orange

Rewards:
Kai Soul Stones