I wanna explain that just like most Villains, Imu also has his Version of Three Top Commanders
They obviously lead Three different Armies & They can be easily seen just by looking at WG's Fodders
There are Cipher-Pol Fodders, Prison/Slave Camps Fodders & Knights Fodders
Cipher-Pol Army is led by CP-0 (They represent CD's Shield)
Prison Fodders (Those who force Slaves to work) are led by ??? (Not revealed yet)
Knights Army (Only seen in Mary Geoise) are led by Holy Knights (They represent CD's Sword)
CP-0 Main Members are Masked Ones & there are Seven, their Commander In Chief is Lucci & He represents Imu's Third Top Commander
Main Warden in Mary Geoise is Unknown but He should be Imu's Second Top Commander
Holy Knights are confirmed to be Nine without any Clear Leader-Figure who should be Imu's First Top Commander
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Long ago i said that Zoro is gonna Fight Magellan during this Saga as his 4th Main Post-TS Fight due to his DF matching Zoro's Fight Patterns
However, it's possible that Imu's Top Commander will instead Eat it (Meaning Magellan might be next to Die)
The Fact that Holy Knights are WG's Main Enforcers & Strongest Warriors they got, it makes total sense that their Leader was the one sent to Kill Doflamingo (Who will instead Survive & Escape thanks to Magellan's Sacrifice)
As Luffy's Sword, Zoro's Next Main Fight gonna be against Leader of Holy Knights
As Luffy's Shield, Sanji's Next Main Fight gonna be against Lucci
- Lucci appeared this Arc which is common for Third Commanders just like SHs faced Jack, Mr. 3, Satori, Cracker ... etc before War starts
As for Imu's 2nd Top Commander, He should be defeated by Dragon himself, just like Oda gave Previous Rebel Leaders such a W, including Kyros, Wyper & Inurashi (Being Warden who keeps All WG Slaves in Check, Oda will use him to show Dragon's Rage! He is most probably Dragon's Hype Tool just like Wyper Fodderized Shura)