Yeah, why did you delete it Brandish?
Imo, I don't think Zeref is menacing AT ALL. Sure, he was a threatening figure till the end of Tartaros and the hype surrounding him was quite big tbh. However, considering how he's been contradictory (can't blame him tbh) all this time, for e.g : I'll kill Natsu, I love Natsu, I'll kill Mavis, I love Mavis etc its hard to see him as someone dangerous nowadays. Heck, even his own subordinate Irene called him a naive person.
However, I don't think we should mistake this for how powerful he is. I think he is more powerful than Irene or August and so obviously should be taken seriously. And with FH in his hands, maybe, soon enough - he'll become VERY dangerous.