On both 1st Edition and Shadowless cards, this reads: 1995, 96, 98, 99 Nintendo, Creatures, GAMEFREAK
The trigger event doesn't have to specifically refer to legendary permanents or to artifacts, nor does it have to specifically refer to when something "leaves the battlefield." For example, an ability that triggers "whenever a creature dies" would trigger twice if a legendary creature or an artifact creature dies while Gandalf the White is on the battlefield, as would an ability that triggers "whenever a permanent is put into a graveyard from the battlefield." Look at each legendary permanent and each artifact as it exists on the battlefield, taking into account continuous effects, to determine whether any triggered abilities will trigger multiple times
"The 'legendary' term was reserved for the rarest Pokmon and typically the most powerful
Spells that can alter combat in your favor like Deceiver Exarch and Cryptic Command are especially valuable to let Marvo survive to attack again
Being able to power out a turn four artifact that ramps, gains you life, grows your creatures, AND draws you cards is way too much
A life-manipulating deck that replicates the abilities of LINLINs Soul-Soul Fruit