Howdy all! Still relatively new to LoL.

[Axel Daemon]

Wow I'm liking what that item does, I can probably switch between that and Lich based on the circumstances.

I also realized Rift Walk is a real cheap way of removing everyone's B. Veil.

 

[Carmine]

Wow I'm liking what that item does, I can probably switch between that and Lich based on the circumstances.

I also realized Rift Walk is a real cheap way of removing everyone's B. Veil.

I would rather replace Guardian Angel or Void Staff for the spell vamp item, Lich Bane adds quite a bit of survivability (Move speed and Magic resist) and damage. It can really work wonders if you need to split push with the large increase of damage to the tower and the increased movement speed, as Kassadin usually does not want to be in a team fight right when it starts and he can traverse from a side lane to the location of a team fight rather quickly.

But really it is up to your judgment, part of maturing as a player is knowing when to build what item. Your build should never be totally set in stone and should be followed more as a basic guideline. Starting with Catalyst lets you do this, if the enemy team is targeting you quite a bit and you feel you will need extra survivability you can grab a Banshee's, if you feel safe you can go with the Rod of Ages. Deathcap is a must have in pretty much every caster build, and Archangels really helps Kassadin, but the last two items are really up to your judgement. I feel that Lich Bane amplifies everything you want to do as Kassadin, Void Staff will help your damage quite a bit if the enemy team is stacking magic resistance, and Guardian Angel functions a bit better on Kassadin because of his ability to riftwalk out of the middle of the enemy if they do choose to focus you, then come back later (possibly with spell vamp) to pick of stragglers.

You should always look at what the enemy team is building and how they are acting towards you so you can build the appropriate items to counter them.