A discussion today came up in the chat regarding NovaBlast's large use of Marks in his Arena decks. MeowMeowCat and godisonlinenow both have seen his decks hold multiple Marks of Air and Fire but without screenshots. I shortly thereafter played against his top ranked deck using the Mark of Gravity and a Colossal Dragon/Gravity Nymph combo. In the 11 turns that the match lasted, he played 4 Mark of Gravitys. His deck still held 40 cards and was doubled (due to Dexterity) confirming this deck has at least 2 Mark of Gravity cards.
The issue was arose that Nova has a high amount of Mark cards despite never winning a tournament (or active on forums under the IGN of NovaBlast). There were also no donations amounting the amount needed to donate to acquire that many Marks.
Attached are several screenshots throughout the match. Post below of your encounters with Nova if you could over the next few weeks when his mark changes.