Jenos has a very good DPS. If at any point you can catch Ruckus while he is distracted with someone else and focus him down, not even Emitter will save him before you've gotten him dead or low enough to be killed by someone else on your team.
Use your "Through Time and Space" ability when Ruckus activates his own ultimate ("Hexa Fire"). He can't move while using it, so you'll hit him definitely!