Ignoring the bad grammar within a number of the mega events there is a flaw (or perhaps a bug) with one of them. 

Assassination

The flaw (or is it a bug?) is that a race you have no diplomatic contact with declares war on you. Even with this event there is no diplomatic contact established so no diplomacy can be conducted . In short until you actually do come into contact via the normal in game means you are at war with no means of ending it. NOTE: this is even more flawed in that should you subsequently then have the Peacekeeper event occur you now have those going through your empire. Should this happen early in the game (and it has happened several times so far to me - about 1 in 3 new games I've started which is most probably bad luck but still) its a huge blow with no hope of recovery as you cannot end the war going on because of the lack of diplomatic contact. You might be able, through great luck, get a ship around the peacekeepers but hard to do if you cannot establish new colonies/starbases to extend the range you ships can move so that you can get into contact with the race you are at war with. I would suggest that either there is diplomatic contact because of the event or only those races you are already in contact with are eligible for the event.