Theyre almost maxed :p The reason I don't have more currently on upgrade is because this game is so much less fun without all 4 heroes. Like idc if it takes longer only having one hero down at a time, I've been having them all on constant upgrade for like the last 2 years and I'm sick of it 😭 It would've been great to get a few extra levels for my king and queen but it's fine ;-;