I’m not sure where you got the figure of 4000 from?
The recent patch notes for Toby, which increased his ultimate damage, say:
- Increased the damage of Core Discharge by 15% (313 per second to 406 per second at Level 5)
- Increased the damage of Core Discharge after selecting Toby’s level 10 Left Helix Augment, Triple Charge by 25% (375 to 563 at Level 10)
Taking his level 5 damage, that’s 406 x 6 = 2436
Taking Triple charge at level 10, that’s 563 x 6 = 3378
Even with skill damage gear (which if you’re lucky with 2 that include this, so max of around 10% total) those figures are only going to get to 2680 and 3715.
Bearing in mind that not everyone is going to get to level 10 in a game (in fact it’s likely that in many games they won’t), it’s more likely that the lower figure is more likely what people are working with.
As for it being the highest DPS ultimate, that’s debatable. I’ve not timed Oscar Mike’s Airstrike but at level 5 that does 13 x 250 = 3250. Rath with level 5 Dreadwind does 83 damage per hit over 4 seconds and can do several hits per second, probably surpassing Toby’s DPS.
Also bear in mind that, even though Toby’s DPS is quite high, he’s slow to move when using his ultimate so it’s not so easy to keep the core discharge on a player or players for the full 6 seconds.