Quick-and-dirty Rakta Cernos build for a friend who isn't big on builds or giga-efficient play. He's a huge [Ivara] player that I've noticed holds down his aim key and goes for phat headshot multipliers while in Prowl. The specific intention was for this to carry you through most content without much issue.

The innate Syndicate effect also gives you good opportunities for laying on extra Viral stacks and energy [Regen], so it's not like the rakta is BAD... Just a little old.

Standard Viral + [Hunter Munitions] setup. Nothing special or pretty but [Serration]'s base damage & Primary Deadhead's forgiving timer allows you to lay on the hurt for a while so long as you pop a head every 12 seconds to keep up with [Galvanized Scope].

Alternatively if you're a god at projectile headshotting you can replace Deadhead with Longbow Sharpshot, as the damage is multiplicative with [Serration] instead of additive. In addition, you can probably add a few forma to swap out Vigilante Supplies for Terminal Velocity for extra ease-of-use. Or, if you're fighting against Viral-Resistant enemies, pop in a [High Voltage] instead of the [Rime Rounds] for corrosive.

Any extra suggestions, feel free to say so in the comments!