[Might be long]
To get a mate,give them a pink tulip in the Fallenclan territory.if your mate is the opposite gender as your character,give them another pink tulip [Wont always be succesful,so it might take a few tries]
To get deathberries,go to the Fireclan's medicine den,become a medicine cat or wait till its a gathering and take the berries
You can click the deathberries and the fish should have berries in it,and you can kill other characters with it
To murder cats,you need deathberries,Leaders,medicine cats and deputies cannot be killed.You can give the fish with deathberries to other cats to kill them instantly unlike the normal berries
[Hope my yapping is helpful.If you wanna ask some more things,you can ask]