It's cool how the group is not just using the terrain to their advantage but also utilize distractions, spells and strategy. Unfortunately for them, the knight looks like he's going to tank the combo attack pretty easily thanks to his armor. In NNT everyone was so strong that armor offered about as much protection as wet paper, so it's nice that it's actually of some use in the sequel. Hopefully things stay that way, perhaps through the introduction of some kind of magical enchanted armor similar to Percival's cape and helm. Nakaba armor's designs are very creative and they are one of my favorite visuals elements in the series, so I would definitely want to see them featured more. I know that they can be somewhat complicated to draw, but perhaps Nakaba could get around that by making them instantly equippable when necessary through the use of some sort of a magic item, so that he would only have to draw the armor during fight scenes.
Considering how outmatched the good guys are, things certainly seem to be heading towards a scenario where Sin will have no choice but to join the fight. I wonder if that could be related to the scene with Pellegarde. Percival and co. are softies that have so far not killed any of their enemies, but Sin gives me the impression that he wouldn't hesitate to finish off his opponents, especially if they happen discover his true identity. Perhaps Pellegarde has to be brought in to observe the fight because none of the Dark Talismans are going to make it out of the forest alive. Maybe he could even be set up as an enemy for Sin to face later on similar to how Ironside is clearly meant to be Percival's main foe.
I wouldn't read into the 3000 year thing too much. There are very few creatures that can even live that long to begin with, but 3000 years is also roughly how long it's been since the first holy war. If Sin is an established character, he would have to be either Meliodas, Elizabeth, Merlin or Gowther, all of whom can be pretty easily ruled out when the dream of the bride is taken into account. There are technically also some Ten Commandment members and archangels who were around during the first holy war, but the demons didn't age while in the seal and the archangels are 5000-6000 years old so none of them fit the bill. Same thing with Gerheade, who is over 4000 years old. If Sin's claim about being 3000 years old were true, he would have to be a completely new character, which would defeat the purpose of making a big deal out of his true identity in the first place. I think Sin was just joking around and referencing Meliodas while at it, which could be a hint that Sin admires him.
Hawk's species can apparently live for millions of years, but they are a bit of a special case given that they are native to Purgatory.