Seriusly now, how do i build Carry Titan ?

It is undenayable that Elder Titan has carry potential, his Astral Spirit gives him tons of pure raw damage(something rare these days), has an aura that reduces base armor(and it is kind of wasted in the support build), as well as +70 AS and 100% Lifesteal talents.

The trouble is he needs too much things to exactly work, and he only has 6 slots
He needs:

-Mana and Hp Sustain early on( Echo Sabre solves one)
-Someway to initiate on people( Shadow Blade or blink, but still they are sub optimal)
-Is possible the most Black King Bar Dependent on the entire game ?
-needs -armor itens in the first place ( Desolator and Assault Cuirass are 2 slots)
-needs a way to have people in place so he can hit them(you will need Echo Sabre + Skull Basher/ Monkey King Bar/Sange Yasha
-A Monkey King Bar because everygame has Evasion.

How do i do this ?

I've seen some people trying to play Elder Titan carry in my team, it's really strong especially in the early-mid game.

The most common items I've noticed were the following:

• Solar Crest, which is always a strong pick especially versus heroes with a lot of armor. Right now it has a win rate of over 60% on Elder Titan which is really strong. Let's not forget about the extra evasion/accuracy it grants, really good value.
• As you've mentioned, Echo Sabre is a wonderful item since it grants you some good stats and the double attack with the Astral Spirit bonus damage is really scary. Right now it sits at over 55% win rate on Elder Titan, really great synergy on him!
• One of the most popular items these days, Mask of Madness can be pretty good on him as well. Once you've casted your abilities and you've received the bonus damage, getting the huge attack speed bonus greatly increases your damage output per second. Not picked up too often though, has a win rate a bit over 55%.
• Desolator is a great item overall, I would pick it up only if I could do it pretty early, since it's most effective in the early stages when the enemies don't have too much armor and the armor reduction is at its best used. Nevertheless a strong item, consider picking it up if you don't need more survivability. A bit over 60% win rate, good stuff. Works well with Assault Cuirass indeed, with Solar Crest too if you'd like!
• Shadow Blade / Silver Edge are useful both for initiation and escaping. The bonus damage it gives for the first attack should not be overlooked, it can turn your first hit into a strong burst damage source, especially if you have some bonus Astral Spirit damage. Let's not forget that it forces the enemies to spend gold on detection which delays other items.
• Black King Bar if you're having trouble with the enemies disables. If they have abilities that can go through it and are targeted, maybe a Linken's Sphere might be more fitting.
• Skull Basher / Abyssal Blade are pretty obligatory since they give you much needed control. Keeping the target in place is one of the main issues of Elder Titan and these items are the way to go.
• Monkey King Bar is nice to have but if you already have Solar Crest I think it's not worth it anymore since it'll grant you accuracy too (less but still cost efficient). I guess it's the best to go for Monkey King Bar though if the enemies rely heavily on evasion.
• Another item that has a win rate of over 67% that shouldn't be forgotten is Deadalus. In combination with Echo Sabre, Shadow Blade / Silver Edge and bonus damage from Astral Spirit, it could instantly burst down a hero.

After all, it's a matter of situation and preference, try out anything that looks good and see what works best!

Medallion of Courage -> Sange and Yasha

Gives mana, -armor, and prevents kiting.

Solar Crest also deals with evasion now.

Shadow Blade/ Silver Edge is also really good as extension. Blink is underwhelming, even in a utility build.

It would really help if Echo Stomp didn't break Shadow Blade invisibility, it would make him very much viable.