As of late last year, when IS changed the arena scoring, there were about 4.0K-4.2K ranks in tier 21 of arena game mode. About 1.2K+ players were able to maintain tier 21 weekly. The season that was just ended yesterday, I noticed that there were only about 1,093 maintained their tier 21 status. Total rank in tier 21 arena is only 3,641.
In tier 20, there were about 14K ranks last year. This past week, there were only about 11K ranks in tier 20.
Arena Tier 21 Cut-off Score – Water Season
Arena Tier 21 Cut-off Score – Earth Season
FE Heroes Arena Tier 20.5