With the Monster Lab you can Rank Up your Monster with another 5 Ranks .
Each Monster’s Rarity can expand his level limit as follows:


COMMON
45 ★
50 ★★
55 ★★★
60 ★★★★
70 ★★★★★

UNCOMMON
65 ★ 
70 ★★ 
75 ★★★ 
8 0 ★★★★ 
90 ★★★★★

RARE
80 ★
85 ★★
90 ★★★
95 ★★★★
105 ★★★★★

EPIC
95 ★
100 ★★
105 ★★★
110 ★★★★
120 ★★★★★

LEGENDARY
105 ★
110 ★★
115 ★★★
120 ★★★★
130 ★★★★★