Trader has riroyku airknight parshath, don't think I'll be able to grab both today, riroyku or rir and 1 airknight in deck?
IMO, you really need at least 2 Riryoku, not juust because they help greatly in farming decks, Cerberus most notably, but also because they are quite useful in standard beatdown decks, especially if you haven't farmed Joey for Metalmorph. Airkknight Parshath is a cool card, but it doesn't have the versatility of Riryoku.
Parshath sucks. 2 riryokus will be useful in many high score decks
airknight is probably best. riryoku is great to have as a surprise trump card, but I have run two before and it's nipped me in the butt because it was a dead draw.
Two Riryokus are useful (I would know), but few decks actually require more than one. Airknight Parshath, on the other hand, will be especially useful, if you already have 1 Riryoku.