I would highly suggest against using him at the moment as he will cause you a lot of frustration... unless you like witnessing some pretty mind blowing bugs.
I have started to record them, even though I am not pvping anymore at the moment with ferno, so yea.
In the recorded instance somehow shade applies spirit link with wildfire on him, even though it obviously says immune, game also doesn't annouce the ability correctly. Then shade proceeds to top that by beating my team with 0 hps lying on the ground dead.
I have also had a hopper on the opposing team apply wildfire to my own team with no ferno on the opposing team (the hopper had wildfire on him). I have also had the reflect dmg viperia bug mentioned previously in this forum very recently. Among a literal slew of other bugs, ALL happening when i use ferno.