I see that the Living Legend of East Blue was too great to be in this. Between the 3, Arlong is the strongest so my money would be on him. Although in a Battle Royale, the strongest could attract the most attention and cause the other two to gang up on him, and together they would beat Arlong. The ones left Kuro and Krieg, despite Krieg's superior strength, I'd lean towards Kuro. I think Krieg would struggle too much with his speed. So maybe Arlong 2/3, Kuro 1/3.