Night-living units

I want to create some cool night-living units, but the only unit I can come up with is a Vampire who takes damage during daytime and gains life when dealing damage. Life regeneration, the sight range and the use of Shadowmeld seems to be the only things that have other effects during night time. Does someone have any cool ideas?

Perhaps you'd like to take a metamorphosis ability that switches between a normal unit and a unit that constantly loses life.

Use a trigger to add the metamorphosis ability to your nighttime vampire at dawn and force him to use it, and then remove the ability from the resultant daytime vampire. Perform a similar action at dusk.

You'll also need something to take care of whether or not he's dead at dawn and dusk.

Hm, just look at the unit stats. Attack damage/types/rate/blah. Walking/flying. Fast/slow. Ethereal/not. Etc.

What about putting a negative health regenration and setting its type to "Only during the day"?

Clever.

you can also make an if, then, else action in triggers so that certain abilities only work at night not sure if theres an if for what the time of day in GUI

There's gotta be a condition for game-time I'm sure of that.

There's millions of things you could do though, what you really need are two triggers, one for when things switch from day to night, and one for night to day. Then in each trigger you can have things like some units turning invisible, different abilities turn on and off, speed changes, etc.