Final answer:
The victory of the Last Alliance on the Slopes of Orodruin was bittersweet due to the high cost in lives, the loss of significant figures, and the incomplete resolution of the conflict by failing to destroy the One Ring.
Step-by-step explanation:
The victory of the Last Alliance on the Slopes of Orodruin in J.R.R. Tolkien's Middle-earth, as depicted in "The Lord of the Rings," is bittersweet. While it marks the end of a great evil and ushers in a measure of peace, the triumph is overshadowed by a high cost—numerous lives, including key figures among the Allies, were lost.
The subsequent periods of peace are haunted by the memories of sorrow and sacrifices endured during the war. Furthermore, the victory remains incomplete as the One Ring, the root of the problem, is not destroyed, leaving the door open for the potential return of darkness. This bittersweet outcome mirrors common historical themes where significant victories are achieved at great expense, and the consequences linger long after the immediate triumph.