Xel'Cruz, the Pillager

Xel'Cruz, the Pillager can't be countered.
Flying (This creature can't be blocked except by creatures with flying or reach.)
Ward (Your life total can't change.)
"In Tarkir's history, there have been two colorless dragons Ugin and Xel'Cruz. Xel'Cruz was hunted down back in the original timeline."-Sarkhan Vol