Yes. It was mentioned by an NPC in the Maldraxxus quest "Blade of Blades", where he boasts about slaying Titans with this "PROFOUND WEAPON", and how he slew lots of guys from the Light, from the Void, and even meddlers from the Gardens of Life.
https://www.wowhead.com/quest=57284/...lades#comments
It's funny, cause when you actually find the blade, it's unimpressive asf. Meaning, the guy's a cocky idiot. But the Gardens still likely exist.
Even the "dreadlords" talk about the Adherents of Life, their plane, and the planes heavy connection with Ardenweald in the Enemy Infiltration: Preface book. Seems there is a vulnerability within Ardenweald that could lead into the Gardens and its fall. Also doesn't help that the Heart of the Forest within Ardenweald is kinda...the thing that's keeping the Jailer stuck in the Maw.
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My assumption is that Sargeras' blade and powers were amp'd up by Anima, and Sargeras empowered Argus, who was full of corrupted Anima. Then, once Argus died, the corrupted Sargeras anima from within Argus went back to its source, right to the Arbiter.
Meaning, Fel corrupted dark Anima >>>> Fucks over the Arbiter's body. That breaks the machine of Death, which then leads to the drought, which THEN leads to the Jailer finally making his move. The Jailer apparently has a history with fucking over the Cosmos, especially the Legion and Sargeras.
No cap, they wrote Sargeras as a big dumb idiot.