Lancaster's Vision
Lancaster and the other nobles are very blunt with Edward as to what they see happening as a result of Edward's continuing favoring of Gaveston. In a vivid image, Lancaster threatens, "Adieu, my lord, and either change your mind / Or look to see the throne where you should sit / To float in blood, and at thy wanton head / The glozing head of thy base minion thrown" (I.1.129-132). First, this image is striking in and of itself; it is extremely violent and unsettling, and indicative of the collapse of the realm. Second, it is striking because Lancaster even has the audacity to utter such words before the king in the first place. Clearly Edward's behavior has rankled them to the point where they are able to be so openly defiant.
The Devices
Edward asks the nobles what their devices are, and Mortimer describes a tall cedar tree with eagles perching on top, but one in which up the bark "a canker creeps me up / And gets into the highest bough of all" (II.2.18-19). Lancaster describes his as a flying fish "Which all the other fishes deadly hate" (II.2.24), and which takes to the air and "there's a fowl / That seizeth it" (26-27). These images are thinly veiled references to Gaveston, a veritable cancer and a despised creature, and Edward certainly recognizes them for what they are.
Gaveston's Happiness
The audience/reader can speculate as to how much they think Gaveston is truly in love with Edward versus how much he enjoys the power and prestige and perks of being his companion, but this image he creates to explain how happy he is to see Edward again is a charming and evocative one: "The shepherd nipped with biting winter's rage / Frolics not more to see the painted spring / Than I do to behold your majesty" (II.2.61-63). It is all innocence, cheer, harmony, and delight—all the more to contrast with what actually happens to the lovers.
Edward's Rage
After Gaveston's death, Edward flies into a terrifying rage and utters some of the play's most powerful imagistic lines. He says, "If I be England's king, in lakes of gore / Your headless trunks, your bodies will I trail, / That you may drink your fill and quaff in blood, / And stain my royal standard with the same, / That so my bloody colours may suggest / Remembrance of revenge immortally / On your accursed traitorous progeny, / You villains that have slain my Gaveston" (III.2.135-142). Here he is acting the part of a king, though an incensed and violent one, and is promising the same destruction his nobles promised him.