Before the invasion of Soul Society in Bleach's Thousand-Year Blood War arc, Yhwach, the Quincy King, specified five individuals capable of turning the tide of battle. Bleach's five "Special War Powers" (also known as the 5 War Powers or the 5 Special Threats, are all uniquely powerful individuals who can resist the mighty Wandenreich better than most other Soul Reapers can.
Source：https://www.cbr.com/bleach-soul-society-5-special-war-powers/
