Peter Robinson (69) is one of the major figures in Northern Ireland's political landscape.
A founder member of the DUP, in his four decades years in front-line politics he has been First Minister, Executive Minister and DUP leader. He also served as the MP for East Belfast for 30 years until his defeat by the Alliance Party's Naomi Long in 2010.
Mr Robinson announced his intention to step down as First Minister in November 2015, some months after a suspected heart attack. He was appointed an honorary professor at QUB earlier this year.
Dr Andrew Crawford was a special adviser to several DUP ministers, including Arlene Foster and Michelle McIlveen.
He resigned from his highly-paid role just minutes after it was announced that a public inquiry was to be held into the Renewable Heat Incentive scheme, and 24 hours after he was named by a senior civil servant as the DUP adviser believed pressing to delay RHI cost controls.
Emma Little-Pengelly is a former DUP special adviser in the Office of the First Minister. A QUB graduate, she worked as a barrister after leaving university. She was co-opted to the NI Assembly in 2015 to replace veteran DUP MLA Jimmy Spratt, who had retired on health grounds. Mrs Little-Pengelly is today MP for south Belfast.
Michelle McIlveen was elected as an MLA for Strangford in 2007. A former teacher, she is also a graduate of QUB.
She was appointed Minister for Regional Development in 2015, and later moved to Agriculture, Environment and Rural Affairs in 2016, where she remained in charge until the collapse of the Stormont Assembly in early 2017.
Timothy Cairns was special adviser to Jonathan Bell when the latter was Minister of Enterprise, Trade and Investment. He was also a special adviser in the Office of the First and Deputy First Minister (OFMDFM) when Peter Robinson was First Minister. The University of Ulster graduate and barrister first worked for the DUP in 2002 as a policy officer, becoming a special adviser in OFMDFM in 2012.
Mr Cairns is now on the board of cross-border business body InterTradeIreland, and is also Wales and Northern Ireland director for the Community Transport Association UK.