Project Spark

Press and choose "Challenges".

There are 3 types of challenges: Timed, Milestones and Goals.
Timed
You have 2 types here: daily and weekly and they reset respectively daily and weekly.

Challenges regarding Seph
* Arcane Missile: while in overflow (Credit to TheDude722)
* Arcane Power Streak: Magic half
* Volley Streak: Magic half, keep it half. Do not go over the second half and do not let it run out. Better to tap than to hold it.
* Arcane Power: Regen magic
* Powered Blast: Hold (level 7 required)
* Overflow Kill: Full Magic Bar,

Milestones
You can unlock those several times (tiers), max tier = 11. The higher the tier, the more XP/credits you earn.

Challenges regarding Seph
None

Goals
You can only achieve those once.

Challenges regarding Seph
* Seph Level Up: Reach level 1 - 20 with Seph
* Seph Bolt Kill: Kill an enemy with an Arcane Bolt attack
* Seph Blast Kill: Kill an enemy with an Arcane Blast attack
* Seph Torrent Kil: Kill an enemy with an Arcane Torrent attack
* Seph Powered Bolt Kill: Kill an enemy with a Powered Bolt attack
* Seph Powered Blast Kill: Kill an enemy with a Powered Blast attack
* Seph Powered Torrent Kill: Kill an enemy with a Powered Torrent attack
* Seph Overflow Missile Kill: Kill an enemy with an Arcane Missile attack after reaching the overflow state.
* Seph Overflow Nova Kill: Kill an enemy with an Arcane Nova attack after reaching the overflow state.

Note: Some powers/attacks are only available after reaching a certain level.

Im posting this solution because the other 2 didn't seem explanatory enough about 1 daily with seph.

The one called Daily: Seph Volley Streak is when you have half arcane/mana/blue stuff and you just hit X, don't hold it or it doesn't count, tap X at the enemies at half arcane.

Achievement has been discontinued due to the server shutdown. It's impossible to unlock this now. No Challenges are available.