Minimum range build to keep your defense target safe without annoying the entire squad.

1. Aim at your defense objective or whatever you wanna protect.
2. Hit 4 on your keyboard.
3. Hit 2.
4. Repeat after 60-90 seconds.
5. Optional: If you don't know exactly what you're doing I recommend not using any other abilities.

Arcanes:
You can use whatever Arcanes you prefer/own with this build. I threw in some defensive stuff since I'm only using it in higher level missions (Guardian, Grace, Barrier). Energize is another helpful option.

Build variations/Helminth:
This is a very basic build, so modify it as much as you want or can. You can easily replace [Corrosive Projection], [Intensify], or [Redirection] with anything you prefer. In terms of adding subsumed abilities: Go ham as long as it works fine with low range.

Hint:
You always switch phases when doing a dodge roll (default hotkey is tapping Shift). This can save your life since enemies outside your phase can't hit you (and vice versa). Any player caught in it can leave the [Limbo] phaseshi(f)t by dodging.

Edit:
SCARLET SPEAR EVENT: Don't use this build. I recommend at least 100% range and lots of duration, then add Vitality and maybe Adaptation. No strength required. Done.

Questions? Feel free to message me ingame or via Discord. :)
Warframe tips and beginner's guide here.