There are 10 grades (rarities/tiers) of monsters, Both, soul drop chance and capture chance are NOT determined by rarity alone, but are a good indicator.

Grade Rarity
1 Common
2 Uncommon
3 Rare
4 Very Rare
5 Epic
6 Heroic
7 Ultra Heroic
8 Legendary
9 Mythic
10 Divine
11 God (not implemented)
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