Nerds Shadow Demon
Shadow Demon is an intelligence hero who can be played as a support or caster core. He has great wave clear and damage ability (Shadow Poison and Soul Catcher), while also having setup and save (Disruption). His main weaknesses are a low effective HP pool and the lack of any kind of mobility.
You can use Disruption early on as a tool to abuse your good base damage for better hit trading. You will be lacking mobility before you'll get to Blink Dagger, but you can compensate it by using Shadow Poison to scout territory. Your goal to just get levels as fast as possible and start nuking enemies down. With blink, you can start aggressive lane push by killing creepwaves with shadow poison and running away as soon as you feel somebody's coming. Splitfarming and lane shaving will help you to get items and levels faster, while also creating space for your team.
This build is partly based on SlashStrike's guide: https://dotaguides.com/core-shadow-demon-guide/
Skill Build Timeline
Disruption at level 1 allows you to secure bounty runes and range creep denies. You max poison first, always, since it’s your farming and wave-pushing tool. After that you want to level Disruption and Soul Catcher simultaneously, with Disruption being maxed first because its cooldown scales significantly better.
May be worth skipping at lvl 6 since it's not as significant in terms of damage, but slow and constant purge are very valuable
Main farming/damage tool When trying to solo-kill on the lane, both your Disruption and your ult essentially give you 1 guaranteed stack of Shadow Poison. This means that as soon as you hit 2, you can Disrupt, hit a 3rd + apply Catcher, step back so you’re less vulnerable, ult when they come out and hit a 4th one.
-1.25s Shadow Poison Cooldown
This is probably the most one-sided choice of all, the cooldown reduction is what sends this hero into OP territory, Shadow Poison basically becomes your auto-attack, it takes you only 4 seconds to insta-kill a creepwave from two screens away (if you’re good at aiming), it takes you 5 seconds to pop a hero for 2000+ damage, etc.
+15% Shadow Poison Damage
movement speed is no joke, and this hero runs around a lot. However, once again the 25% Shadow Poison damage is just a huge difference maker.
2 Charges of Disruption
charges of Disruption basically means you have no down-time, no weak moment where ‘oh, he used Disruption, I can go on him now’, because you always have another one ready. You can save 2 allies, save an ally and get illusions of the enemy carry, disrupt 2 enemy cores, save an ally and yourself as well, the possibilities are endless.
Blink increases your safety-zone massively when split-pushing by giving you an escape, as well as increasing your catch-range by a ton, since blink range is also boosted by lens.
Even while you have Shadow Poison, you still would like to go for Hand of Midas to get a lot of benefit from your level 10 talent and use your early advantage to get the item early.
Scythe of Vyse is obviously always good when you just need a hard disable versus slippery heroes, and further boosts your solo-kill potential.
Eul’s gives you yet another disable / set-up, more movement speed and can also function as a Linken’s breaker which enemies will often pick up against an SD.
Force-staff, similarly to Eul’s can act as a Linken’s breaker (the cheapest one) and boosts your mobility. Whether this is a good pick-up or not generally depends more on the enemy team and how many of their heroes are countered by Force (heroes like Riki, Clock, Ursa, Sven, etc.)
Agh’s gives you 3 charges on your ult as well as adding the Break effect, obviously good if there are any passives to be broken (it pierces BKB, unlike Silver Edge), but also just for controlling multiple enemy cores that don’t have mobility spells (sometimes better to have 2 more purges than a hex versus melee carries with immunity or that buy BKB like Jug/Naix/Sven/Luna/Troll)
Tranquil Boots are an absolute must, for merely 500 gold you are almost doubling the MS you get and also getting more HP regen than a pipe gives you. The only down-side is that they deactivate when you attack or get attacked – well GUESS WHAT, you never attack and if you play properly you should very rarely be getting attacked also!
It not only gives you incredible solo kill potential, but also provides you with the structure damage you lack to go with your amazing wave-clear. In the standard Disruption->Hammer combo, you can shift-queue Soul Catcher while channeling the hammer – since the meteors take 0.5s to land, that gives you enough time to apply the amplification even before for the initial damage.
Lotus Orb is another great item that you can either put on whoever is front-lining or save for yourself to deal with enemy silences.
Aether Lens is your first core item. It allows you to initiate with Disruption and also use hammer on towers or Disruption targets from much further away (fog, trees, etc.) all of which is absolutely crucial for this build. It also makes the Soul Catcher much easier to land, lets you ult pretty much anyone you want in fights, and lastly the range increase on poison is also noticeable although not the biggest deal since its range is already massive.
Aeon Disk is pretty good in a lot of games as a 4th or 5th item because enemies will try to jump you first since you’re a saving hero, and between the 2.5s of Disk and 2.5s of Disruption you have enough time for a guaranteed blink out.