Thoth S4 OP

Pros
[*] Ridiculous late game damage
[*] Ridiculous range
[*] Amazing at sieging tower
[*] Very unique kit/Really fun to play
[*] Ult snipes
[*] Lots of poke damage; also very safe poke due to range

Cons
[*] Really struggles clearing early
[*] Early game is basically sitting in your tower until 10 minutes
[*] Things get real bad real fast if you miss your abilities, especially the stun
[*] Cripples ruin Thoth; can't dash
[*] Positioning is really really important

You want to start with SoT and Bumba's most of the time, SoT is pretty straight forward, 10% cdr level 1 is insane, 20 power and mana sustain, Bumba's is still good for mids despite the change where the closest player with Bumba's gets the benefits. It helps clearing camps a lot so you can get back to lane quicker and not miss the wave. After that, pen boots, pretty straight forward, then dynasty plate helm, book of thoth, chronos' pendant, ob shard, tahuti and then don't sell dynasty helm until you can buy spear of desolation instantly. Once you have ~1700 gold, then sell dyansty for ~1100g and you can buy spear of desolation and maximize damage.

If the other team has healing and it's being a big issue, you can replace spear of deso with divine.
If you want to have a ton more damage upfront and want to sacrifice cdr get a bancrofts and replace chronos.
If you are dying too quickly grab an e staff and replace chronos.
If the other team is running triple tanks or something like that, you can replace chronos with a soul reaver for the % health true damage.