After much delay:
Name: Mad Jack Churchill. Born Hans James Brackon-Steiner of Caledonia.
Callsign: Vicious. Originally followed by 'B*stard' after the most common description of the vitriolic Mechwarrior, it was shortened when it caused confusion on the 'comms.
DOB/Age: 25th March 2983, 48 years
Current Mechs: UM-R60 Urbanmech “Taysider” and a modified JM6-S Jagermech “Steel Lady” which totes quad AC2s and ten tonnes of armour. Also owns a devastated xxx-xx Champion.
House Affiliation: Nominally House Steiner, but it varies from day to day. He seeks to 'redeem' himself when hungover and guiltridden, but seeks revenge for what he sees as the 'unfair' treatment he received from his family.
Military History: Trained at NAIS, he graduated at the bottom of his class, though not for lack of talent. The young noble happily frittered away his time on drink, whores and gambling, attending classes only when forced to. Upon graduation, he was pressed into service in the LCAF, transferring from unit to unit, eventually being dishonourably discharged.
Physical Description: Older man with receding black hair and a drooping walrus moustache. He has the appearance of a heavy drinker (Which he is), and is waddling to fat, but the soft coating belies the heavy muscles honed by thirty years of bar fights and assorted other petty violences. His clothing is low quality, ragged and spotted with grease and stains, in a variety of styles. They are clearly worn for comfort and cleaned at convenience.
Open Background: A bitter, angry mercenary down on his luck, 'Mad' Jack Churchill has been floating around the Inner Sphere and periphery for nearly 25 years. He's gained a reputation as a psychotic drunk, and hence earned the 'Mad' part of his moniker, Mad Jack (Little do they know, he chose the name Jack Churchill to gain the nickname). Originally piloting a JM6-S Jagermech, after nearly losing the 'mech in a brutal firefight against the LCAF Hans James Brackon-Steiner once served he has spent the last ten years brooding in his cups about revenge more and more, piloting an UM-R60 Urbanmech and gained a feared, if little spread, reputation as a devastating urban combat fighter with a lifetime of dark fury rising to the fore, his fierce intellect coupling with his native talent, professional training and experience to ambush, harass, and rubble his current enemy. His R-60's AC-10 is famed for always being on target, and equally famed for refusing to die regardless of how much return fire Mad Jack inevitably fails to dodge in his furious, bloodthirsty rage.
Deep Background: A disinherited and banished son of minor Lyran nobility, he is the offspring of a lower tier Steiner military officer and an Isle of Skye merchant's daughter. Lazy, hot tempered and exceedingly arbitrary in his decision making processes, he was a constant disappointment to his parents. Disinherited following his dishonourable discharge from the LCAF, he stole his father's Jagermech and ran. With nothing to his name but the clothes on his back, the Jagermech and it's ammo, he joined on with the first MercCorp offering him a ticket off planet. He has not returned to the Isle of Skye Federation in 25 years...until today. After p*ssing off the wrong person, once again, he jumped on the first ship heading out of Davion space - realizing only too late where he was going. But 20 years have passed since the last bounty hunter tried to chase him down for his father's mech, and Solaris VII is famous for it's money making potential...
On Solaris VII: Jack quite quickly made a name for himself, unfortunately not a good one. After destroying a news van and botching the apology Jack has often found himself as the object of ridicule – but rarely to his face. Often at loggerheads with Randolf von Bremen, the two have developed something approaching a grudging respect. The kind of grudging respect only two seasoned cheaters could have: Both need the other strong for their own purposes. That was what it meant to be used by a friend, that they would want the use to make you stronger, not weaker.
Bizarrely making Von Bremen one of the closest friends Jack had on Solaris. His only other friends were his technician, Dan Abnett and his fellow mechwarrior DeMarkus Frankfurt. The scruffy Warlockian had struck a chord with the former Caledonian pirate, and several hours had been whiled away drinking in his hospital room until the nurses caught them talking {Scrap}, most of it mech or woman related, and kicked Frankfurt out. He also received a couple of visits from Bertie Walker and his daughter Heather – with considerably less alcohol.
It was his last match that had put him in hospital. Nearly miraculously remaining unscathed for the duration of the match despite the level of punishment being inflicted on
Taysider, the final devastating ram action finally did him in. The force of the impact had slammed the cockpit into the core of the mech, pulverising the internal structure – and Jack. Suffering from whiplash, cracked ribs, a dislocated shoulder and multiple lacerations and burns, the fat pirate had still been chortling when the EMTs put him under. A one thousand C-Bill bounty remains unclaimed for any picts featuring the look on his victims face.
During his recovery, Dan Abnett had recruited Rick “Mop Boy” xxx as a second technician for Jack. Between the pair of them they had finished the repairs on
Steel Lady, bringing the venerable battlemech back to full working order for the first time in over a quarter century. With Rick’s aid, replacement parts for
Taysider had finally been acquired and the two were in the agonizing process of rebuilding the Urbie from the ground up.
Lemme know if I missed anything. Should have time to write tomorrow as I'll be in the car for 7 hours, so seriously. Suggestions welcome

At a minimum, expect a Jack reentry post.