Raids are the endgame mode in the launch notes, separate from the five story worlds. The featured raid is the source of the Secret that unit pages call Sokonu (King) and raid pages call Sukuna. Roger is the other Secret, and he is indexed under banners, not this raid.
What the fight asks for
The boss walks the path and spawns extra minions. You need area damage for the adds and single-target damage for the boss. Enemies in the raid are described with shields. Roger bypasses shields. Goju's aura is the tick damage players use when a shield has to come off over time. Megomu and Foji slow the wave so the damage has longer to land.
Party play is reported to raise the boss's total HP. A solo clear avoids that multiplier and still has to meet the damage check. There is no published HP number.
Drop
Player notes put the Secret drop at 1.5 percent. One walkthrough adds a 100-clear pity. Another note says an official pity number for secret units was not documented. Look at the raid reward screen. If a pity counter is there, use it. If it is not, do not plan around 100 clears.
The raid also drops evolution materials, including Cursed Fingers for this unit, and a Raid Shop spends raid resources. Honored Eye is named for the Goju evolution and can come from raid content. Counts are not published. The evolution fee is still 100,000 coins when you craft.
Before you queue
Field a team that already clears Nightmare. Spedwag still matters because the fight is long enough to need upgrade gold. Do not enter with undocumented mythics as your only damage. Sokonu's own kit wants dense waves and takedowns, so he is a better farmer of other content than he is a requirement for his own raid.