Assuming they were working on DS3 already, they were probably two years out from release. Let's assume the payroll was $1MM/month. That's $10,000 a head, with salary and benefits for 100 people (just an estimate, I see 111 on LinkedIn). So that's $24MM right there. Then you've got rent, power, utilities, software licenses, dev hardware, contractors (voice acting, outsourced concept and/or production art, localization, etc.). Maybe that's $5MM. Then there's publishing costs, so throw in $10MM to market the game, and another $2MM for distribution and other expenses.
So, if you bought Vigil Games for one dollar, it'd still cost you $41MM to actually develop and publish DarkSiders 3. But if it only sells 800,000 units, at a net of $40 per unit, that's going to end up being a $10MM loss.