A Poisoned Chalice (Fate/Zero, Fate/Grand Order)

For each Master, a Servant. For each Servant, a Master. The relic system was never introduced, and every Master in the Grail Wars has always received a Servant based on their own personality alone. Now, the Magus Killer goes to war - and receives his greatest weapon yet. But even with all of Assassin's skill and treachery, can they stand against the raw power of the Fourth War?