I’m not leveling 5s yet (although I have LotL as my one green 5 when I get there)
In other green 4*s I have C-Melendor, Hansel, and C-Caedmon leveled and trying to decide who next:
Kalo - he’s great even though nerffed and I have no Attack All greens
C-Gaderius - overheal and Attack All
Peters - I keep reading about the compliment to Hansel
Thoughts?
0 voters
I voted Kalo and I don’t think it’s that close.
Mana control and silence is so helpful, always. Kalø is great too of course but I think I’d do Peters first. 
Overheal will also help on survival, so Gadeirus would be my next choice. Just me though, each to their own 
C.Gaderius is a great option for a true support hero don’t forget he gives attack boost as well so the rest of your team will be much stronger. Pairs great with Mel just in case you need a heal before the overheal
I voted Kalo based on hero overall quality but I think other two options are better suited for OP. Probably Peters as a first option
I agree with @Gwniver , especially given that Peters is useful for tournaments and especially event stages. Kalø isn’t amazing helpful IMO.
Without Hansel, I’d say Peters. But OP already has Hansel so I vote Kalo first. Peters can be next
I don’t find hit-all heroes for 4* to be particularly amazing (although costumed Wu Kong is not too bad, and Li Xiu can be annoying). Here, for Green, Kalø’s hit-all special is weak and he is slow, so you would want to use him for other reasons, and you probably need to emblem him up in order to use the other parts of his special skill well, as he needs to survive his team-mates. Since you are still new to the game, it would be less urgent to consider such a strategy in team composition.
Peters is a good complement to Hansel and Caedmon because of their similar speeds. Activating them together could help you kill off specific opponents, and stop/delay their using their specials, giving you more time to charge up Hansel/Caedmon/Peters to snipe more opponents. (This provided you are stacking Green to some extent.)
As for costumed Gadeirus, it depends if you want to put costumed Melendor and costumed Gadeirus in the same team. Many players like to use an off-colour healer (maybe costumed Rigard for cleanse) in a 4-1 ratio.
In my honest opinion, you would probably get more use of either Peters or Costume Gadeirus.
Kalo is still good after the nerf but only in certain situations, events and tournaments….
Given that you already have Hansel, I would go with Costume Gadeirus
Whichever hero you choose good luck
At your stage in the game id leave kalo as when yah gonna use … Only maybe in rush situations.
© Gaderius is a soild hero plus that the over heal can come in handy for map levels or events .
Peters slicence is also a nice tool to have …
Im going peters as with hansel they go well as mentioned you can shut down two heros …
Do you have an overhealing hero at all? (Or if you do, other than Grevle?)
Overhealing is strong – in PvE, it often means you can go into the boss wave with something like double normal hit points. That cGad also throws an attack buff (and not just any buff, but Boldtusk-level buff) and actually hits all for some damage makes Mr. Robot a strong all-around hero you can use a lot. --Plus, being a Paladin makes him even sturdier to stick around and keep buffing and healing.
(If you do go with cGad, you might use original Melendor alongside rather than cMelendor, just so you can get an immediate normal heal, then invoke overhealing-over-time atop the result.)
Don’t get me wrong, Peters is a nice control hero with better sniping than Hansel, and he’s Fast, so part of that decision is how many heroes of what speed you have as well. (If you already have a lot of Slow and/or support heroes, some Fast strikers might round out your current roster better.)
Kalo… look, he’s ridiculous when he pulls off his stunt (and especially in Rush), but any hero who requires some, most, or all of the rest of the team to be dead before his schtick really works sounds like someone I wouldn’t use much on offense, at least. And sure, yeah, I want my raid/war defense to be good and all, but I prioritize heroes I am actively using myself when I’m picking and choosing.
To me, the context of your team is what matters the most here. If this was just a poll with those 3 heroes and zero other info, I would vote Kalø (if I voted at all, because without other info a vote might not be very helpful). However, with the provided info, I agree with @JGE and the recommendation of leveling C Gaderius. Overhealers are incredibly helpful for many aspects of this game (and that fantastic attack up is also helpful). Having a well rounded hero selection for different aspects of the game allows you to start getting more rewards, which will ultimately allow you to progress faster. My only caveat here, is that you enjoy taking part and want to complete the different parts of the game. I think we should all play in the manner we enjoy the most 
Por ser rápido, iria no Peters primeiro. O meu me ajuda bastante, tem pancada forte e silencia o alvo. Kalo depois, vai arrasar nas guerras e eventos de arremetida. 
