A Telkine in Egypt is the third main quest of Act 2 in Titan Quest.
You need to go to the Valley of the Kings and search for the Tomb of Ramses to kill a Telkine. Thankfully in Titan Quest you do not have to search for the right tomb, you can always find the Tomb of Ramses in the same place - northwest of the Portal.
Aktaios is a pretty easy fight so long as you avoid his worst attacks. The pillar behind me in the screenshot above is my favorite one to stand behind during this fight. If you are Melee you'll need to come out from behind the pillar to damage Aktaios but ranged can hide behind it the whole time.
Most of Aktaios' attacks will hit this pillar rather than you if you stand behind it and Aktaios will almost never come up to you because he likes to stay in the middle of the arena where his Light of Ra attack can hit you.
With Aktaios defeated you will want to pick up the Cuneiform Tablet and return it to Imhotep who is at the Temple of Seti in Thebes. Doing so will complete this quest and begin the next and final quest of Act 2, The Sickle of Kronos.