This is my high duration [Harrow] build. I personally prefer to have a longer duration build for [Harrow] mainly for the 15 second invincibility but also so there can be less time micromanaging all of his abilities and focus on which abilities will help your squad at the right time and [Primed Continuity] and [Narrow Minded] do this for us. After all [Harrow] is predominantly a support frame.

Too many people use [Redirection] or other shield mods with [Harrow] because of Penance, however, shields only buff the duration of the Penance ability not the strength of the buff, that is ability strength. The maximum duration for the Penance buff is 120 seconds and with this build (with no extra shield mods) and max overshields from Condemn is 111 seconds which is easily enough time for the buff. This is why [Umbral Vitality] is used not only because it makes our Umbral Intensify stronger but to add extra tankiness especially in missions that deal toxin/viral damage to us. [Primed Vigor] is another good option here if you still want extra base shields. [Natural Talent] is essential for [Harrow] as his abilities have a very long casting time and his buffs only work once the ability animation is over.

[Stretch] and [Augur Reach] are used to nullify the range penalty from [Narrow Minded] and also give us a little boost, plus, [Augur Reach] converts the energy we spend on abilities into shields which makes Harrow a little less squishy and allows us to use and/or refresh our Penance duration with that new bout of Shields. [Energy Siphon] can be switched for anything I'm just a fiend for energy.

I welcome any suggestions to this build and this will be what I put onto my [Harrow Prime] once he is released in the next month or two.

I also have a budget build for Harrow if you want to do what this build does but don't have enough endo or the correct mods. This build is here... https://overframe.gg/build/246068/