I know this is kinda an unconventional build, but i have 8 winning streaks with this build. It's kinda fun too!
Skill build will depend on how good/bad your lane is. If you can easily harras their offlaner, then max 3. If you need to keep trading hit, max 2 or at least skill up 2 points. I normally start with orb of corrosion and phase boots. Then rush radiance. Once I have radiance, I can pretty much join the team fight. Then the next item will be the satisfying aghs.
This is where the fun starts. With +150 infest damage talent, you can pretty much nuke any supports. Basically when you infest the enemy (not your ally), you get free hits, slows, radiance burn, life steals, disarming, and big nukes at the end.
Then depending on how the game goes, I usually like to buy BKB on top of rage. Basically all you have to do is to survive for 20secs (yes, aghs reduces your ulti). So buy whatever you need to "get inside" your enemy over and over again (yamete kudasai senpai!!).
There was a match where I had to buy BKB, Linken, and Manta just because the enemy team had many silence and cc. You might think "bro, you deal no damage with that build". But in fact I dealt over 150k damage in that match, even my items were not built around high damage items. Abyssal is also a good choice if you need lockdown, infest will also proc bashes.
Source: https://www.reddit.com/r/DotA2/comments/11prgxq/do_you_like_lifestealers_aghs_cos_me_likey_so/