Your post is oddly ignorant of two things. One is that with Imbuing, one can make custom equipment.
Yes, you can dedicate your efforts toward gathering the materials to crank out a massive stock of high-end weapons for every conceivable encounter. Or you can just add Chivalry to your template. Guess which one everyone does.
If memory serves the Shadow Knights are vulnerable to energy damage.
Whoops, now we're looping around the gauntlet and we're back to the Darknight Creepers. You did bring a fire damage undead slayer as well as an energy damage undead slayer, right? As well as a physical damage demon slayer for the Abyssmal Horrors and a fire damage demon slayer for the Impalers? I hope you didn't bring an Exiler for those Impalers, because the Exiler may be a demon slayer, but it's 100% energy damage and they're invincible to that.
Gee, this is so much easier and better than just bringing a demon slayer, an undead slayer, and casting Consecrate Weapon. Odds are that without Chivalry you're just going to bring a couple of mixed-damage slayers, do really suboptimal damage to everything, and hope for the best.
Two, Critical Hits from Lightning Strike, the last I heard, were direct damage, meaning damage that isn't subject to resists. In other words it should do damage about equivalent to an Armor Ignore.
This fact was exploited often by archers who were fighting the Tentacles of the Harrower, on which ranged damage is nerfed. All the nerfing in the world doesn't matter, however, when every third or so hit is doing Armor Ignore level damage for the mana cost of a Lighting Strike!
Fail. Even at 120 Bushido you'll need to fire off an average of five Lightning Strikes for a total of 25 mana to score one critical. (The non-critical Lightning Strikes aren't free.) Fire off an Armor Ignore every fifth swing for about the same cost and there you go. Sure you're not getting the hit chance bonus from Lightning Strike, but then again you're not stuck hitting for single digits the rest of the time because boss has 90% in one resist either.
And that doesn't take into account the interplay of Perfection and Critical Hits, which can make for damage that simply has to be experienced to be believed. In your example, and assuming I understand the mechanics correctly, then the resists of the Shadow Knights, or any other creature, shouldn't matter one bit.
You're forcing me to bust out the math.
Assume that Mr. Samurai is attacking the Shadow Knight with an undead slayer Blackthorn Kryss. Assume he has 100 tactics, 100 anatomy, and has already built up to max-level Perfection. Odds are he won't get to use Perfection AT ALL since only one person can use it on any given creature, any damage or even a strength buff prevents it, etcetera, but let's just pretend.
His base damage will be 40 to 49. Let's assume he also hits for max damage, just because. Since he is hitting against the Shadow Knight's 90% physical resist, he will do... 5 points of damage. Wait, he's got a slayer weapon, I mean 10 points of damage. Woo we're cooking with gas now.
Meanwhile Mr. Paladin also has 100 tactics, 100 anatomy, and is attacking with an identical Blackthorn Kryss. Since he's casting Consecrate Weapon, he's hitting against the Shadow Knight's 55% energy resist.
Without Perfection he hits for 30 to 37 base damage, and to be fair we'll assume he hits for max as well. Since he's hitting against 55% resist, however, he's hitting for about 17 points of damage. Whoops, slayer weapon again, I meant 34 points of damage
or almost three and a half times as much as Mr. Samurai hits for.
And he hasn't even cast Enemy of One yet!
"But Skrag, criticals! CRITICALS!"
If we generously assume that Mr. Samurai has 120 Bushido, one out of every five Lightning Strikes will generate a critical hit. Since this critical will hit against an effective 0% resist, it should do 98 points of damage if we assume he keeps hitting for max.
Wow, that's a lot. But wait, let's average it out. Our Samurai hits for 10 damage four times, and 98 damage once. That's a total of 138 damage. Meanwhile our Paladin has hit for a consistent 34 damage five times, a total of 170 damage.
The Paladin is outdamaging the Samurai by a wide margin, even if the Samurai has 120 Bushido, gets the correct number of critical hits, builds up to max Perfection, never loses Perfection due to missing, and the Paladin is a giant idiot who forgets to cast Enemy of One.
Once he does cast Enemy of One, this quits being a contest at all and becomes a joke.
The only time the Samurai will outdamage the Paladin will be against a creature with resists equal across the board (Dark Fathers, and pretty much nothing else anyone cares about) but even that is dependent upon the Samurai getting a pristine and untouched Dark Father, then honoring it before anyone else does and before it can buff itself. Then as long as he never misses, Perfection should allow him to keep up with Enemy of One, with the criticals putting him ahead.
Needless to say, this isn't terribly common or likely, and certainly isn't worth smacking things for 10 damage other times. Or 0 damage if you're the schmuck who brought an Exiler to the Impaler room.
I think I'm going to stop my participation in this discussion there
Yeah, you probably should, but not for the reasons you think.