Dralan, The Crossguild

Whenever a creature named Dimir Guildmage or Izzet Guildmage enters the graveyard from anywhere, put a +1/+1 counter on Dralan.
{b}{u}{r}: Sacrifice a Dimir Guildmage or Izzet Guildmage, double the amount of +1/+1 counters on Dralan.