When I'm playing I am playing extremely aggressive to the point of almost in the enemies faces, however I am trying to stay as close attention to teammates as I would try to get to them and defend then with power siphon to gain as much shots as possible to then charge the enemies, hit them with the shots, jump and stun them to repeatedly beat on them. Try and gain as much ult charge as you can and when you have ult and see a huge firefight, jump in and make the enemies kill you using ult making them disperse if possible. Try to also hold narrow doors or halls as you have a greater vantage being close and personal with the enemy, using your jump and stunning to make them unable to attack giving you time to attack them, make sure before they get up to use power siphon for at least 2 or so seconds when they jump up, giving you time to think of what you can do next, either attacking or running.
How I attack when I'm face to face is by jumping and running around the enemy hitting when I can and using power siphon to block bullets or surrounding bullets and bombs elsewhere. Try and use your calamity shots , even if no charge, it can do a lot of base damage helping teammates or yourself in a fight. face to face I would jump from one to the other quickly, confusing the enemy at times and sometimes making them run to try and find cover. You can use your power siphon to defend from almost all oncoming projectiles, including ults, like skye's time bomb, Imani's dragon call flames, etc..

Crush
Shatterfall
Shatterfall Stuns enemies hit for 1s, but no longer Slows.
Level 1

Devastation
Calamity Blast
Heal for 240 for each enemy hit by Calamity Blast.
Level 4

Necromantic Might
Power Siphon
Reduce the damage required to generate a Calamity Blast charge by 300.
Level 3

Playing God
Power Siphon
Heal for 20% of the damage Absorbed by Power Siphon.
Level 4

It Watches
Armor
Generate 6% Power Siphon charge for each enemy hit with Massacre Axe.
Level 2

We Can Rebuild Him
Armor
Receive 10% increased Healing while at or below 50% Health.
Level 2

Wrecker
Weapon
Your weapon attacks deal 90% increased Damage to Shields.
Level 3

Nimble
Armor
Gain 21% Movement Speed.
Level 3

Morale Boost
Armor
Increase your Ultimate charge rate by 20%.
Level 2

Guardian
Armor
Increase the effectiveness of Shields you create by 20%. This does not affect most cards and passives.