Lotsa Numbers

- He knows his Unholy Emperor, to whom he was fiercely loyal, was betrayed by the Serpents and slain soon after being mortally wounded in his final battle with the Highlord of Heaven - who would later perish as well.

- He and his minions were holding the Angelic Host, on their own, as rearguard. When he noticed something was amiss the other Hellish Kingdoms on the other side delayed him from reuniting with his master.

- His armies were decimated, many joined the Serpents, Hell could not afford creating another front due to a massive-scale civil war.

- He retired back to his realm, followed by those still faithful, and submerged within the Phlegethon to heal his wounds. His domain is pretty much one gigantic supervolcano with jagged steep cliffs, and a massive platau at its top, where large pools of blood are mixed with magma at the center to create the sacred river which pours down like a massive waterfall

- He healed first, then declared them War when he refused to attend the Gathering of Kings.

- He no longer commands an army large enough but his realm possesses tons of natural defenses (high cliffs, high-tier Fiends both on the surface and within innumerable caves and scorching magma-filled tunnels) which give him and his followers insanely boosts to their defenses, using them to his advantage.

He does not need to launch a major invasion into other kingdoms or DIS itself since he knows ways to provoke them into attacking him. Not only serves him as an excersise but as a test for those under his rule also.

- Because This Is Violence!

- Eruptions are frequent in Violence. Artificially creating a super-massive one not only would nighly impossible (considering the complex natural defenses within the great mount) but suicidal as well: the Kingdoms of Horror, Sorrow, Oblivion, and Envy, as well as the main Gate of Dis would dissapear in an instant; leaving the door open to the Heavenly Host. The Forge would cease to work, paralizing all high-quality weapons and armor production and earning a technological edge to Heaven.

Fianlly, loosing the Phlegathon and the Blood Falls would dry the wells of DIS which are needed to keep something of incalculable value within (or beneath, rather) the Unholy Citadel functioning, thus dooming all Infernal-kind.

- Mocking the Queens of Horror and Sorrow's ineffective mental stratagems upon his troops.
- Mocking Greed's attire and the 'low quality' Angelic feathers he wears proudly. A great insult, when you consider that the ones present on his head belong to the crippled Grandmaster of the Heavenly Council afterall (An ancient Seraphim)
- Ravaging every single enemy incursion with ease and rubbing it in front of their Lords and Kings.

- Greed often replaces his defeated armies with unevenly skilled troops. He gets endless flocks of newcomers to DIS every day willing to join and serve him. Additionally he, much like his brothers do, restricts their growth in power.

Violence doesn't. He lets his minions gain strength in order for them to challenge and conquer every hazzard present in that kingdom, and his king too if needed be

- Would you honestly do that if you were in his place? The richest mo-fo in Hell, surrounded by powerful sycophants who may or not be working for your treacherous brothers under the table? (kind like you're doing?) Would you really leave your precious Vault and your beloved Cornucopia unprotected? No.

You send your armies and the majority of Lords to oversee things personaly in the field while you comfy stay back protecting your precious stuff. Since they're probably plotting shit against you, some of them might just die and get replaced easily.
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- And let the third one make his move? Nahhh.