So I was able to find some low quality Korean raws, and luckily for you all, I speak that so here we go.
Natsu and zeref have their little standoff, and natsu addresses zeref as "zeref" which surprises Invell. Apparently zeref never revealed his true name over on his continent. Invell recognizes the name and actually appears worried. Zeref orders Invell and the rest of troops to retreat and head west because he and natsu are literally going to lay waste to the land with this fight. Oh my yes!!!
Happy mentions that Natsu is going to use "That" as soon as possible, which he does. Natsu unravels his bandages revealing a dragon tattoo (this makes me worry about natsu turning into acnologia-like dragon). Zeref is actually surprised by the amount of power flowing from the mark.
Natsu and Zeref then spar a bit. Natsu lands zeref through a wall, but zere gets up like it was nothing and throws a death ball at natsu. Natsu miraculously BURNS the death ball away, shocking zeref. Natsu then appears to take the upper hand, landing some serious blows against zeref, but zeref merely picks himself up and questions natsu on his new power.
Natsu explains to Zeref that his new tattoo is....
THE LAST OF IGNEEL'S POWER!!!!!
bestowed to natsu as igneel's last wish. Natsu explains that he needed ten months to focus the power, and that once he uses it, it will never return. Zeref remarks that with the power of the dead perhaps natsu actually has a chance to defeat him.
Natsu then enters Fire Dragon King Mode!!!! A new mode with few visible differences, but a whole impressive power boost. Natsu then burns the ground away. Yes, the actual ground is burning away like paper to a candle.
Zeref then has a nostalgia moment thanking certain people by name Igneel (i guess because he's the one to give natsu this power) Anna (no clue who she is, idk, their mother?) Layla (Lucy's mom, lol wut?) Mavis (okay, i guess cause romance stuff) and finally natsu himself
All this happens as natsu launches possibly the most powerful attack seen to date in the manga.
EDIT: Chapter 465 will be named 400 Years, I do not know what the title to this chapter is.