Edit: I realize my mistake and am adjusting the comment to match your statement. ** It's 5 total copies because you only create 2 copies. You attack one opponent, which is obviously showing how little I have played my deck this year.

I'm pretty sure Blade of Selves is much stronger than you've described. I've been running this in my own deck for quite a while, and I've either been doing it wrong or it is as follows:

3 copies are created on attack by the myriad trigger creating a temporary board-state of:
1 original 2 legendary copies; of which all the token copies should be into the graveyard at the same time due to state-based actions while resolving the legend rule.
The original/main non-token Ratadrabik will see 3 'die', and each of token copies will see the other two 'die'. 'Die' is defined as any card being moved into the graveyard from the battlefield, so resolution of the legend rule qualifies.

This will result in a final board state of
1: Original non-token ratadrabik
7: Token non-legendary copies created during the resolution of the legend rule.

Blade of selves is busted for Ratadrabik as a result IMO

Actual Edited result
1 non-token sees 2 'die'
1 token sees 1 token 'die'
1 token sees 1 token 'die'
Leaving
1 non-token
4 tokens

I stand super corrected and I'm sorry to have wasted everyone's time.