Despite being a franchise primarily aimed at younger audiences, violence is an integral part of Pokémon. When a Pokémon faints in battle, its eyes turn into comedic swirls to help draw attention away from the fact that it was just beaten into unconsciousness, but these injuries are often superficial and easily treatable. Perhaps unsurprisingly, because at the end of the day it's still Pokémon, there aren't any tales of Pokémon battles with fatal repercussions. This line in the sand begs an important question: can Pokémon die?
Aside from the number of times that Ash Ketchum has canonically died during his journey, the animated series is actually overflowing with definitive proof that Pokémon can indeed die. Even Pikachu has died alongside Ash a time or two, as early as the series' first season when they were crushed by a chandelier. Despite Ash and Pikachu taking their deaths in stride and using their new noncorporeal forms to torment Brock and Misty, the episode is still a jarring example of the realism among the absurdity in Pokémon.
The most famous example of the possibility of death in Pokémon would have to be Ash's experience with Charmander in the anime's first season. It's well known that if the flame on a Charmander's tail goes out, the Pokémon will die. When Ash and the gang happen upon an abandoned Charmander that's hiding under a leaf in the rain, Pokémon made perhaps its first step into true life and death stakes.
Ash himself is no stranger to watching Pokémon die. In the film Pokémon: Lucario and the Mystery of Mew, the titular Lucario sacrifices its life by using up all its Aura in order to save The Tree. In Pokémon, I Choose You!, a young trainer's Luxray freezes to death trying to keep him warm when they're trapped in a snowy forest overnight. During Ash's Alola adventure, his Litten, prior to being caught by Ash, lived with an elderly Stoutland that ultimately succumbed to old age, much to Litten's grief.
The Stoutland's death in Pokémon the Series: Sun & Moon was noteworthy because it was confirmation that Pokémon can indeed grow old. There had been examples of elderly Pokémon in the past, but the unmistakable confirmation that a Pokémon could truly die of old age was startling. Pokémon in the anime and films have most often died by sacrificing their lives for the greater good, but a wild Stoutland that simply got old is a harsh dose of reality.
Death has been around since the early days of the Pokémon games as well. In every iteration of the Kanto Region, from Red & Blue, FireRed & LeafGreen, Let's Go Pikachu & Let's Go Eevee, etc., Lavender Town remains home to Pokémon Tower, a cemetery for Pokémon. In fact, most games in the franchise feature a Pokémon cemetery in one form or another, cementing the fact that Pokémon not only can die in the games' lore but do die. The recurring inclusion of a Pokémon cemetery is noteworthy because the franchise has not shied away from removing content from the early games in the past, such as the removal and retirement of the Game Corner.
The upcoming game Pokémon Legends: Arceus is already rife with death despite not being due for release until late January 2022. As with all pre-release Pokémon games, new Pokémon are starting to trickle out, and some of these new creatures that populate the Hisui Region games have startling Pokédex entries. Hisuian Zorua is said to have been forced from its home to resettle in the Hisui Region, where the species could not adapt to the harsh weather and died out, returning as a vengeful Ghost-type. Basculegion, a new Pokémon, is comprised of the souls of Basculin, its pre-evolved form, that died in a perilous journey upstream.
In Pokémon's defense, no Pokémon has ever seemed to have died as a result of injuries sustained in a traditional trainer battle. However, the games and anime alike have confirmed many times over that Pokémon can die from old age, the actions of humans, the environment or self-sacrifice. Pokémon are living creatures, and dying is the one thing that all living creatures can be equally counted on to do, but that the franchise is so open about it is an interesting tactic. For a series that thrives on making pets fight for money and rewards, yet doesn't want to encourage gambling, Pokémon tows a strange line with its frequent portrayal of the death of innocent, often adorable creatures.