Metroid vs Honkai: Star Rail

Connection:

Both are genetically modified interstellar armored space hunters of their respective games and operate across the stars travelling from planet to planet where they are famed and feared for their deadliness and effectiveness on the field

Both are in possession of a high-tech armor (Power Suit and SAM respectively) which often causes them to be misgendered as males when they are actually females beneath in order to keep their true identities under anonymity

Both are trained and engineered to become highly skilled and effective armored super-soldiers as they were the products of genetic modification (Samus being infused with Chozo DNA and trained to become the ultimate warrior while Firefly is a genetically engineered human and effectively raised to become an Iron Cavalry Knight)

Both are considered the sole survivors of their planets (K-2L and Republic of Glamoth respectively) after it had been devastated by an alien invasion (Space Pirates and The Swarm)  that left them deeply traumatized by their horrific experience. Both were left alone in the universe before they're taken in and guided by a mysterious master who gave them a new purpose and lease on life (the Chozos and Elio respectively)

Both developed an illness that was gradually eating away at them physically and mentally yet despite the toll it had taken on their body, they continue to persevere and carry forth their given objectives (Samus was infected with Phazon and then with the X Parasite while Firefly has suffered from Entropy Loss Syndrome)

Both once lend their services to a military force (Galactic Federation and Iron Cavalry respectively) at some point in their lives before they adopted their current "space hunter" profession and developed a noteworthy reputation across the cosmos (Samus becoming a galactic bounty hunter and Firefly becoming a member of the Stellaron Hunters)

Both are pragmatic, determined, ruthless, and formidable warriors with the capabilities of devastating entire worlds if they have to get the mission done where underneath that standoffish and reserved exterior is a deeply shell-shocked woman who are not without a kind and endearing heart as their lives were plagued by tragedy and hardship but nevertheless, they manage to persevere and solider on ready to take on whatever challenge that comes their way