Thanks to everyone for their inputs.
By king and queen, I meant in terms of market value and most sought after coins.
Also, if arbitrage is difficult then what about algorithmic trading?
What are the best bots around for algorithmic trading?
Crypto space will always have one King and it will be
BTC in any term. All the other coins can name themselves whatever they want.
Any type of trading is "difficult" and risky, arbitrage trading though doesn't only boost your trading volume but your trading risk as well.
IMO your best chance, at least in a matter of integrity and seriousness, is
Gunbot.