Please look at the video again.
Look up the MID BOSS FIGHTS part, halfway trough fighting and when he jumps down.
You'll see that he suddenly stops, no doing anything, then an orange cloud surrounds him. At first I thought that was the Dragon soul or even the dragon fire, but since the same thing happens with the ice dragon, that has an ice breath, that's not the case.
It is definitely some kind of other option, like a potion, a perk or even a cheat.
I considered that, as shown in my OP. Point is, he did not have a healing spell in hand and perks, quick buttons for potions, or Todd using a hacked build are all unconfirmed. What IS confirmed is auto-heal and we have video of a form of auto-healing. Bethesda would be wise to clear up how it works because as of now the most logical conclusion is what was shown.
The demo character was in Todd mode. If you really think that we'll be able to insta replenish our entire health bar, in mid combat, with the health regen mechanic, then I don't need to be having this conversation with you because you don't understand.
Edit: Exactly what Bukee said.
So your only argument is "if you aren't naive enough to believe it will be perfectly fine and only positive you don't understand"? Excuse my bluntness, but that's idiotic. Show me a source saying that Todd was using a hacked build that allowed for instant regen at the push of a button and I'd gladly retract the remark but as of now the only logical conclusion is that is how it works