Free Agent - NA
This is a build designed to slap as many Astral Marks on as many people as possible, and ensure that your team will always* win teamfights since they just refuse to die'.
*: Not 100% guaranteed
':Will probably still die and blame you anyway
This works best with a 2 tank 2 damage team, as so long as you have some awareness you shouldn't need the flankers, and you can counter any flanks with Void Grip, as long as you relay that you have someone grabbed they should die within the next 4 seconds, plus most flanks cannot take advantage of the benefits of Jenos anyway as they are too far away. Practice the buddy system, and stick together so you can keep your team well stocked on health on point.
As always, most HP sponge tanks such as Torvald work as a great synergy with Jenos, and high-damage champs such as Dredge or Cassie will become significantly more powerful with a Jenos Quick-Fix on their team.
Just about any talent will do you fine here, aside from Binary Star, but I prefer Luminary due to the damage buff that comes with the AM, which a good chunk of your team will have applied a good chunk of the time. I recommend you build Chronos for CDR, everything else is largely down to situationals and personal preference. Just do not ever under any circumstances take Veteran.
Astral Cycle
Astral Mark
Increase the duration of Astral Mark by 1.6s.
Level 4
Retrograde
Astral Mark
Reduce the Cooldown of Astral Mark by 2s.
Level 5
Lightyears
Astral Mark
Increase the range of Astral Mark by 16%.
Level 4
Relativity
Astral Mark
Heal for 40 every 1s for 10s after applying Astral Mark.
Level 1
Heavenly Pull
Void Grip
Increase the range at which you can use Void Grip by 10%.
Level 1
Luminary
Astral Mark
All allies already affected by Astral Mark are Healed for an additional 285 when you use Astral Mark.
Level 1
Chronos
Armor
Reduce the Cooldown of all your abilities by 30%.