What heroes do you already have maxed? & Where do your priorities mostly lie (titans, events, offensive raiding/war, war/regular defense)?
Without knowing the details, I can say:
It’s going to be between Kage, Ursena, Panther and Jabberwock. The others can definitely wait (unless you’re in desperate need of a healer, where Marie could be of some use, but I’d hope you have 4* heroes maxed for that); Grimble & Sargasso don’t even make the cut
- Kageburado and Jabberwock are both all-around great heroes - being the two most versatile of the bunch due to their speeds, attack stats and hits. So if this is your first purple 5* going to 80, I’d be choosing one of these two (Kage more offensively and Jabberwock more defensively to help you choose)
- Guardian Panther is one of the best purple heroes in the game, and creates such an amazing synergy when paired with other offensive purples (especially if they also hit 3, or have fast mana). So if you’ve already got at least one offensive purple to pair her with, maxing Panther could give you the most bang for your buck. She’s got an incredibly high attack stat, so great in a stack and vs yellow titans, not even including her elemental defense down (which also makes her great for those very same things). + She dispels, so great utility too. So again, if you already have a few purples maxed and your priorities lie more toward titans and offensive raiding, I’d go Panther
- Ursena is a power-house in the defense department, being one of the best tanks currently in game, so if that’s where your priorities lie - she may be the right choice for you. She also shines vs holy titans if you need the extra survivability, and can be awesome to raid with if there’s two or more offensive yellows on a defense team. So if you’re running purple tanks in war and/or prefer defense over all else - go Ursena
It’s going to be between Joon, White Rabbit and Inari. Some others are good, or have their place, but I wouldn’t consider maxing over any of these three. Ranvir isn’t enough of an upgrade to Wu, so unless you don’t even own Wu, not worth the extra mats. Neith has utility, but doesn’t shine nearly enough to make choosing her over the others worth it. & Musashi is a solid offensive hero with solid tile damage, but Joon, WR and Inari have him beat.
- Joon is a perfect choice if you’ve already got a maxed Jackal to pair him with, as these two make a killer team. Also, since he’s a fast sniper, he’s going to be the most versatile of the bunch - as heroes like that always have a place. If this is your first yellow 5* going to 80, I’d probably go this way
- White Rabbit is an important hero, as he’s one of only two heroes that lower defense in the holy element (the other being costumed Vivica, who’s incredibly hard to pull). This makes him an amazing hero to bring in vs all purple titans, and great in a yellow stack. & If you decide to max Joon first, maxing WR next paired with Joon and Jackal will be one of the best trios in the game [to use on offense]. As the utility of defense down works the same at 70 as it does at 80, I’d be making sure you have a purely offensive yellow 5* maxed first before going ahead with him (again, the most bang for your buck)
- Inari is probably not the most popular choice to suggest to max [out of the options], but she’s so fun, I couldn’t help it. Especially if you can pair her with a blind hero + a taunt hero, you can have some amazingly entertaining battles ahead of you - as you become nearly invincible. + Her attack stat is the highest in yellow, meaning she’ll be one of the best heroes to bring vs purple titans for the extra tile damage. Although, if you have no other yellow 5* maxed, Inari should definitely wait - she’s 100% passive, meaning maxing her does nothing but add to her survivability. She’s more of a luxury hero; if you’re still building out your bench, she won’t be of as much use to you [at 80] as the two previously mentioned holy 5*, therefore I’d pick either Joon or WR before ever maxing her.