And now the final Lockheart sibling! Prince and Commander General of the Eukarian Armies Lugia Lockheart.

A very charming yet humble Prince, Lugia Lockheart takes the form of a Lagiacrus which is a curious form inherited from his father's Aqurian origins. He is a mech that really isn't bothered about the Royal side of the job and prefers the military side of his role. He is an army mech through and through, with his passions being simulated battles, training both in the army and the Chelian Academy and Oskin (a deer horse like creature) riding.

However... as you might notice, not is as it seems. He is depicted here post Cybertronian War with cane (that hides a rapier sword), an injured leg and a Cybertronian cannon.

Now for some history:

Lugia Lockheart is the slightly younger twin brother of Katrina Lockheart and born in the Horizen capital Nibel to Dezmi Windwarrior and Sunrise Lockheart. However much to the disappointment of Dezmi, Lugia had no traits of the Watchers within him and thus born with no powers of storm and winds, nor was Sangol/Surahgol (a legendary sword that only answers to the Watcher of the East) responding to Lugia. This caused a rift that, to be honest, never really healed as both father and son kinda resented each other...

Instead of going off the rails, Lugia put his energy fully into the Eukarian Military. Excelling in both academic and physical training in the Chelian Academy, he was quickly promoted through the ranks all the way to the Commander General of the Eukarian Armies at the young age of 25 human equivalent years. During this time he ended up bailing Katrina (in her shifted form) from police jail more times than he could count, helping take care of his baby sister Feenixfire and dating a few femmes (although half heartedly as he was aware most femmes wanted him due to being a Prince.)

When Feenixfire was 21 and Lugia was 29, the Cybertronian War started and the Autobots requested help from the colony planets of similar races. Eukaris was one of the rare few that both answered and sent Eukarian troops to assist in the war. This resulted in the posting of Lugia Lockheart as the main commander of the troops (as well as Feenixfire herself as an ambassador in the Gearverse, this doesn't happen in the Japanverse).

During the Cybertronian War, Lugia commanded both many victories and defeats for the Eukarian army. Being admired and respected by both Eukarian and Cybertronian troops and superiors alike. He was then posted to Moonbase-1 to help keep it off the hands of the Decepticons as a new planetery base.

Now what happens next depends on the Universe:

Gearverse:

Moonbase-1 is attacked by the Decepticons as well as rogue Eukarians, the surprise attack caused Lugia and his forces to be overwhelmed. With the Jurassician Prince he was serving with being killed in the initial attack. Lugia was captured after his leg was blown off in an explosion caused by the Decepticons and sent to Shockwave to be experimented on. This was where he acquired the Cybertronian tank cannon in which was done to 'upgrade' his robot and alt mode. However, before anymore damage could be done, Feenixfire and Gearchange launched a rescue mission alongside the Wreckers and managed to rescue Lugia and the rest of the prison captives. From here Lugia had to spend months in repair as he had lost a lot of inner energon and the leg had been blown to pieces, a new Cybertronian leg was crafted that was able to fit the Eukarian body, marking a landmark discovery for Eukarian medical science.
However, this incident as well as the death of the Jurassician Prince and later injury of Feenixfire while saving her bodyguard. Caused the Eukarian government to pull out of the Cybertronian War and get their troops out. Lugia was transferred back and continued his military career, later marrying a Cybertronian femme called Socket that he met in the war and having a daughter.

Japanverse:

The same attack happens, however it was a plot cooked up by Grimmsbane De Cagliostro to weaken the Lockheart family and eventually take over. Grimmsbane even lead the attack and made sure there was very little survivors. The Jurassician Prince was killed to allow a power vacuum to form for later Chayara to fill and the captured mechs and femmes inc., Lugia were sent to Shockwave.
This started a long process of experimentation in which Lugia was changed, parts added and removed being destroyed and rebuilt beyond recognition. Yet somehow he endured and bided his time... He eventually escaped, destroying the facility and fled in an escape pod. This eventually landed on Earth in the late 1960s where he started attacking human towns and villages out of rage. This was put to a stop by Feenixfire who fought him, tranquillised him and eventually repaired by Baku Sabre. He joined the Eukarian War alongside his siblings and resumed commanding the rebellion against Grimmsbane. Later marrying Socket Sabre and having a daughter.