This is something I discovered while farming Titania ex once I learned about her tether mechanic and started playing with my cooldowns, I'm not sure if the other tanks are able to do this in the way a Paladin can but after some experimentation with the timers I've learned that it's possible for a Paladin to negate both tether mechanics without issue.
For those unaware, Titania has two tether phases where she tethers someone and hits them with lightning that does splash damage, each hit stacks a debuff on the target that makes the next hit very likely to kill them, but it is possible for a Paladin to eat all 6 tethers in both phases due to the timing between. Based on watching timers it appears each blast is fired after 6 seconds. I've also only done this as a Paladin OT, I do this so I can save my cooldowns for the tethers, it's also important the healers top you off after each blast. This should be easy as you will be the only one taking damage during the tether window.
Tether 1- Grab the tether and move to one side of the boss while the rest of the party stacks opposite you, this allows you and the party to continue dpsing while you take the tethers. Tether 1 does it's regular damage and applies the debuff to you. Do NOT pop any cooldowns for the first hit.
Tether 2- Pop Rampart and use Sheltron along with any shields from healers, benefic/galvanize/benison should be enough to let you barely survive.
Tether 3/4- Rampart will still be up for both of these thanks to it's 20 second window, pop sentinel at this point and sheltron again as a precaution during tether 4 if you're worried about Rampart falling off.
Tether 5/6- Hallowed Ground will completely negate the damage from the last two.
I have done this successfully for several runs once I finished experimenting with the timing of the shots and my cooldowns. This strategy will require the MT to solo Fae Light with Hallowed/Bolide/LD/Holmgang for at least the first two hits as you can eat the third hit unmitigated if you need to.
For the second Fae Light, you can soak it with the tank using Sheltron and a bit of extra attention from the healers, you should be able to rebuild your gauge by the time you reach this point.
There is only one other final complication for the second tether phase, if your dps is really good during the add phase (and that add phase will only get shorter as the item level goes) and the add phase is shorter, it's possible that Hallowed won't be up in time for the last two tethers. If that happens, I suggest having the main tank take one hit from the 5th tether and either use their ult or super mitigate the 6th. Hope this useful to other tanks!