None, since this deck is built to be used to farm Pegasus without a specific skill. This means any Legendary Duelist can use this to learn drop skills, but you can use skills to help the deck by using "Balance" or "Switcheroo".
Tribute summon a Millennium Scorpion and attack with the monster to increase the Atk over 6,000.
Summon a Piranha Army and use 2 copies of Riryoku to shift the buffed Atk of the Scorpion to that of the Piranha.
If the Atk of the Scorpion was 6,000, the Atk of Piranha can be 5300 now. Then get it to attack Pegasus's LP directly. Due to the effect of the Piranha, you can achieve "Over 9,999 Damage".
Aim for "Over 9,999 Damage"!
If you have Piranha Army, Millennium Scorpion, and 2 copies of Riryoku, "Over 9,999 Damage" can be achieved. Since the goal of this deck is just to get the assessment, you can arrange this deck relatively freely.
How to inflict "Over 9,999 Damage":
If you can increase the Atk of the Scorpion to 6,000 or more, the Piranha can get 5,300 or more Atk with 2 copies of Riryoku.
So I used Piranha & unhappy girl as to farm Pegasus. In the last round, I ritual summon DMC then I used Martyr and Riryoku and shooting star bow so I can directly attack Pegasus. However it turned out that it couldn't attack and I lost! I wonder what is wrong with my strategy! Thank you for helping in advance!
Hmmm, not impossible & Guardian Statue is actually way better than Clown (more consistent once down). However, might I suggest the main goal being 2 Millineum Scorps on the field, 1 attacking 1 intimidating, & leaving the last spot open. Last turn, summon Piranha, do your Ryoku thing...but with beatdown from Kaiba? That's +600 even if something went wrong or only 1 say Union Attack, or not 100% this deck.