Sigil should double your current health, not add half your max health to it, just played a game with a UB who stacked the shit out of health, and used sigils right before he was about to die, and got several kills from it, since his health went up to like 4000 which was enough to get a kill against the pursuing demigod, who was being shot down by his teammate reg.
Don't say some bullshit like you can use it too, so what if I can, it's still OP, I wasn't playing a health stackin build at the time anyway.
From 500 to 4000 in an instant is total bullshit, he should have gotten up to 750, that's how it's supposed to work.
Not to mention the recharge is shorter then the duration, so if they stack, you can get a ridiculous amount of health.
Using sigils allowed him to play recklessly and wreak havoc on our towers which screwed us over. We did kill him like 4 times but that should have been like 8, we lost cuz our Erebus dc.