Why you (probably) shouldn't be running AD reds (math inside)

Just looking to bring some clarity as to why Armour pen reds are almost strictly better than AD reds on Assassin Nocturne. I've seen it mentioned that "oh it's just personal preference" or something along those lines, but there's really nothing to support it.

For all numbers presented I will assuming AS quints, and the precision mastery. Some people take Intelligence, and it will change the numbers a bit, but not too significantly. I'm also taking sorcery over fury, but that's a tiny difference.

Let's look at some scenarios

Early Game Jungle Clear

A common argument for AD over armour pen in runes is that since not all monsters have armour (or not much armour) you are effectively wasting runes in your early game when it matters most.

Assuming Talisman start (there shouldn't be any difference between talisman and machete for this exercise, and I just prefer talisman), the following are the clear times I had in a custom for the old Valkrin clear

AD reds, AS quints- 6:04

Arpen reds, AS quints- 6:05

Now there is 2-3 seconds margin of error for sure due to pathing/auto cancels and stuff, but worst case scenario is that armour pen is a couple of seconds slower.

So why does this happen? Why does the AD not matter?

Mostly because the armour pen is mostly only "wasted" on small creeps, and due to your AoE with Q and passive the small creeps are irrelevant to your clear speed. The armour of big creeps is

1st clear:

Big Krug-10 Big Raptor-15 Big wolf-10 Gromp 15 Blue/Red-10

So on first clear we waste some armour pen (~5) on Big Krug, big wolf, and the buffs. This might slow you down a tad.

However, by 2nd clear monsters get more armour. On second clear the armour is as follows

Big krug: 20 Big Raptor-30 Big Wolf-20 Gromp-30

Combined with you now getting more AD from a higher rank in Q and you can actually clear faster 2nd clear with armour pen over AD. Add the two together and it amounts to essentially 0 difference in clear speed

Tl;dr- It makes effectively no difference in clear speed

Early game duelling vs enemy jungler, or damage on ganks

On the off chance that somebody invades you and you have the health to actually fight them back instead of just running away, does flat AD do more damage than armour pen to champions?

It is going to vary a bit by level, but we'll say level 4. We'll assume enemy has same armour as Nocturne (35 + 9 from runes = 44). I'll also assume base MR for purposes of thunderlords proc, though this doesn't make a difference really

QE + thunderlords combo does - 187.0 damage with arpen, 186.6 damage with AD. So there's no difference

What about autoattacks- Assuming he's standing on Q he does 71.6 damage with arpen per auto, and 71.5 with AD. If not standing on Q AD wins very slightly (53.6 vs 52)

Tl;Dr- early skill damage the same, auto damage same if standing on Q, negligible difference if not standing on Q

Burst scenario at 6

This is where armour pen is supposed to shine. But how much better is it?

For all burst calculations I am assuming that you know how to use Q before your ult hits to get the bonus AD on ult as well as your first auto + tlords proc.

Level 6 burst with 2 long swords vs a level 5 Caitlyn with armour runes (42.7 armour)

The combo we are looking at is QR passive proc + thunderlords proc and 1 more auto (effectively 2.2 autos worth of damage). We will ignore E because it does magic damage and does not scale at all with AD so it will not depend on rune choices.

Arpen burst = 567

AD burst = 550

So armour pen definitely does more. But is that damage that significant?

The way I like to give this context is to ask "How much more AD would I have to buy to make up that damage difference". In this case, it takes ~5.5 AD added to the AD build to make up the damage difference. At the cost of 35 gold per AD, that equates to 192.5 gold.

What scales better?

This should be evident from above, but we'll put some numbers to it. Always same combo as above targeting squishies (given armour of 24+9 from runes + armour per level based on Nocturne's level)

Nocturne Level	Items	Damage Difference	Gold Value of damage difference
11	Warrior+Ghostblade	68.7	735
14	Warrior+GB+Trinity (1 sheen proc)	80.9	840
16	Warrior+GB+Trinity+Tiamat (include active)	95.6	875
18	Warrior+GB+Trinity+Rav Hydra	104.1	1015

Those are just some sample builds. I tend to build him very very high damage but you might build him less so.

The point is that you are essentially throwing away a lot of damage by going AD reds.

Miscellaneous

Tiny other things to mention

• AD will let you last hit slightly better when you are in a lane. Might make a tiny difference if you're farming a wave under tower after laner died but it's pretty insignificant

• Prior to this patch AD was slightly better for tower pushing. Now towers are affected by armour pen so this advantage is essentially gone

• AD gives you a tiny tiny bit better waveclear with Q, but who cares

REAL TL;DR- Taking AD over armour pen does not increase clear speed in any significant way, gives about 1.5 more damage per auto to champions early, and even then only if not standing on Q, and the difference between Arpen and AD can be worth 30 AD or more in the lategame. There's really no advantage to taking AD, it's not a personal preference thing, and armour pen should always be run over it

If anyone has any questions, or if they have more Nocturne related math questions, I'll gladly answer.

Also I should just mention as a footnote, I do no think arpen reds are only viable option on Nocturne. I think AS is fine, because it at least has different strengths to offset arpen's higher burst. AD has no real benefit and should only be used if you are limited on rune pages.