If you've been having trouble tackling the tank meta, pick Trundle

Just a few pointers about his ultimate:

It does not steal 20% resistance now and 20% over 4 seconds. Rather, it behaves extremely oddly and differently than any other shred in the game.

1. The system checks what amount of armor and magic resist you have at the point of impact.
2. The system then calculates 40% of that number and divides it by half (then stores it into 2 variables as floats, probably as "Initial" and "DoT").
3. The system applies Initial immediately and then applies DoT into several steps over 4 seconds BOTH to your target and yourself.
4. 4 seconds after DoT has finished, both you and your target instantly revert to the previous values before the cast.

Much of this is implied or directly contradicted by the wiki, but it is right because I have tested it. The wiki is incorrect in some aspects. Trundle was ignored by Riot for years, so it has been by the wiki community ;-;

Some implications of this design:

1. the shred does not update. Where BC modifies the target's current armor by -5%/stack, Trundle's ult modifies it by a float that is calculated by a %.
2. What this means is that once you fire that ult, it is going to shred what you would have expected at the beginning and is completely independent from every other source.
3. If Leona is stacking resistances and W's for a total of 230 armor and you ult her when she has 1 second left, you will drain a total of 92 armor. When her ult wears off and she is sitting at 130 armor, you will still be draining 92 armor, leaving her with a pitiful 38 armor. I use Leona as an example because she gets bonus armor from her W for building armor, but this is equally true of every temporary armor/mr buff champion like Xin Zhao, Malphite, Rammus, Galio, Braum, and others.
4. The reverse is also true. If you ult Leona while she has 130 armor and then she W's, you will only shred 52 armor, leaving her with 178 armor, which is even less of a drain than if you just waited until she W'ed (138).
5. You gain armor/mr equal to the numerical shred. Thus, you will receive more armor/mr when Leona's W's than when she doesn't AND it will not update to reflect the buff falling off (or if she uses it after you ulted.)
6. I assume Trundle's ult factors into the order of operations for pen/shred as such:

Trundle ult = weird ass instantaneously mathy magical shit ---- Flat shred -> %shred -> %Pen -> Flat pen

The first differentiation is more or less moot. Trundle's ult is essentially FLAT shred that is based off of 40% of the target's INITIAL resistances. So you're just applying 1 instance of flat shred before another, which is mathematically the same. However, if you were to ult someone before abyssal scepter's aura is applied, you would get more shred than if it was already applied when you ulted. So when you ult, the flat shred's value is based on the initial armor, but mathematically the initial shred is applied BEFORE any successive shreds. So, the only way to delete leona's armor would be if 40% of her armor with her W was greater than 100% of her armor without W. BC applied directly after Trundle's ult will not lower her armor to 0 (my theory.) 7. Because it doesn't directly steal anything, just calculate stuff, your fates are not intertwined. If you die, they still get shredded. If they die, you still get buffed resistances. Not sure about getting healed because that DOES get updated live (his ult will remain the same in respect to % hp if Lulu! ults the target.) Still experimenting. But regardless, ULT THE TANK WHEN THEIR BUFFS ARE ABOUT TO WEAR OFF. THEN BLOW THEM INTO THE 9TH DIMENSION. Ulting the tank and then trying to keep them alive so you can "drain" them is unnecessary. If you can blow them up, then do it. Then tank all the shit with your awesome armor buff.

So ult responsibly and remember,

You can never bash something too many times. -