How does casting spells as a melee character work?

Does mobs interrupt as they are hitting and extending the cast time by a bit or do they completely interrupt a spell when they hit? Also how does blood alter work exactly?

Is blood alter like a set it and forget it spell, someone can cast it and leave it for those to use and do other things or is channeling something that keeps you in casting animation? I guess what I want to know is blood alter like healthstone soul well or is it like a drain life where you "channel" it?

Aeno

@ The blood altar: You simply cast a spell (Which does have a channel time of 1.5-2 secs) that places a little Urn full of blood on the ground.

While the Blood Altar is on the ground it passively heals everyone in the red ring area. <-- That is the cast and forget part.

While the Blood Altar is on the ground, allies can Sync skill with it (Default X key) which they will stop all actions and knee down to heal a greater amount.

The 2 Morphs are.... Increase the amount of passive heal it gives (red ring) OR Allow multiply player to Sync with it at one time + no loss duration time for it.

Most spells are instant and while they have an animation, they don't have a casting time in the sense of a cast bar. Those that do have a casting time don't seem to experience 'pushback' from damage in the way that a game like WoW does it. You can stop a spell from being cast with an interrupt (a weapon bash or one of a handful of powers that have an interrupt effect), by causing the target to lose control (paralyzed/stunned/etc), or silenced (which is a short duration effect). Silence is the only one that's liable to stop an instant effect, though.

Casting animations (whether instant or those with a casting time) do not lock you in place; you can't sprint while doing so, but you can still walk/run. (The same applies to standard attacks, mind you.)

IIRC the default behavior of Blood Altar is that it's a fire-and-forget that's placed in a single spot and creates an AoE HoT. One player at a time (not the caster) can activate it to channel a faster HoT, but this reduces the overall duration of the altar. Morphing the power can change some of this in various ways.

Blood Altar is a skill well worth joining the Undaunted Guild for, the same goes for Persuade at the Mage Guild and Intimidate at the Fighter Guild.