adjudicator
alleviative
alleviator
anodyne
appeaser
arbitrator
assuager
balm
calmative
conchie
conciliator
conscientious objector
cushion
diplomat
dolorifuge
dove
family counselor
go-between
interceder
intermediary
intermediator
lenitive
make-peace
marriage counselor
mediator
mitigator
moderator
modulator
mollifier
negotiator
pacificator
pacificist
pacifier
pacifist
palliative
peace lover
peacekeeper
peacemonger
peacenik
placater
propitiator
reconciler
referee
restraining hand
salve
sedative
machine gun
brought
confidant
consoler
counsellor
depositary
ninguem
statistician
umpire
went
mischief-maker