This build is a work in progress as of the most recent update, due to [Caliban]'s Rework!
IMPORTANT NOTE: It has been confirmed that [Caliban]'s Passive and [Adaptation] do not stack. If you equip [Adaptation], you will gain the higher of the two resistances, effectively losing you [Caliban]'s passive on yourself. For this reason, in my [Caliban] builds, I prefer to treat his passive as a free Adaptation that takes up no mod space, that is why it is not on this build.
My Venato Build to go with this: https://overframe.gg/build/258984/
The original [Caliban] build I had made, focused entirely on Lethal Progeny and being more of a meme build sadly, is retired. It was, in the first place, not an amazing build, although I definitely had some fun times with it, but with this amazing new rework, it no longer functions, and it was time to retire it.
We need a lot of ability strength on this build, but no longer need as much duration as of the newest update. We will mainly be recasting the shield [Regen] sentient, as recasting is now possible. This creates a powerful synergy between all of our abilities that did not exist before. The Augur mod set is very important here, as the wiki says: "Shield recharge is disabled when Shield Gate is triggered and will resume when [Caliban]'s shields begin to recharge itself." In order to ensure we can get shield recharge back as fast as possible, this mod set is the best. You can also use Arcane Aegis as [Caliban] having even the smallest bit of shield allows his Sentients to begin regenerating his shields again.
Sentient Wrath acts as a multiplicative damage buff on affected enemies. Meanwhile, Tau Status now increases the change of other status effects being applied to the enemies. These are great changes, so using both abilities often is a great idea. Sentient Wrath will calculate it's damage bonus AFTER Faction Mods and other damage multipliers, leading to it giving crazy amounts of damage when paired with the right setup.
The Helminth of choice is Eclipse. If using [Caliban]'s shield focused sentient, the other Sentients it spawns have very high threat level. This means enemies will target them, but it's always good to have more damage resist on top of your shields so they don't break.
For Archon Shards, I would use Red Shards for Duration or Ability Strength, whichever you prefer.