<Questiom>How to make a buff-like ability?

How do I make an ability which enables the target an ability to Resurrect in 30 seconds. (Just like a buff)

BUT NOTE:

1.The "Resurrect" is just an example, I want it work even if it's 100%miss(Evasion), Invulnerable, or some skill else.

2.If the caster casts the 2nd buff on the target before the 1st one disappeares, the target should have 1 buff, instead of 2.

3.If the caster casts the 2nd buff on the same target 12 seconds after the 1st one, the buff should disappear 12+30=42 seconds after the 1st buff is casted, not 30 seconds.

4.It the caster casts a lot of buffs on multiple units, they should all work.

5.If possible, the buff should be dispelable.

No one has an idea???emote_confused emote_confused emote_confused emote_confused

Just give the targetted unit a passive ability? With a few triggers, that should be easy. Then also give them a dummy buff, like bloodlust. Only thing is, I don't know if you can find out when a buff is dispelled :)

So maybe dispell won't work, but rest does.

Well, could you give me an exact solusion. 1~4 problems are very difficult to deal (Especially 3rd). You'll find out a lot of difficulties when you are making. So please tell after testing.