I'm a Noble on the Brink of Ruin, So I Might as Well Try Mastering Magic

Botsuraku Yotei no Kizoku dakedo, Hima Datta kara Mahou wo Kiwamete mita @COMIC
没落予定の貴族だけど、暇だったから魔法を極めてみた@COMIC

Source

I'm a Noble on the Brink of Ruin, So I Might as Well Try Mastering Magic
Botsuraku Yotei no Kizoku dakedo, Hima Datta kara Mahou wo Kiwamete mita· 没落予定の貴族だけど、暇だったから魔法を極めてみた
novel

What’s a guy to do when his life suddenly changes while innocently enjoying a nice, cold drink after work? And I mean really changes. This middle-aged commoner now finds himself in the body of Liam Hamilton, the young son of a noble house teetering on the brink of collapse. Between his fervidly desperate father and his utterly apathetic brothers, the only bright side to his new situation is that Liam can finally try learning magic like he’s always wanted. Little does he know his hobby of choice may be about to turn his life upside-down yet again! Will Liam be able to master the craft of magic? And will it be enough to save him from the shadow looming over his family...? (Source: J-Novel Club)

Side Story

I Am a Noble About to Be Ruined, But Reached the Summit of Magic Because I Had a Lot of Free Time. Chris Loves His Master!
Botsuraku Yotei no Kizoku dakedo, Hima Datta kara Mahou wo Kiwametemita: Chris wa Goshujinsama ga Daisuki!· 没落予定の貴族だけど、暇だったから魔法を極めてみた~クリスはご主人様が大好き!~
manga

Chris-chan, a young werewolf girl, is always busy under the care of her beloved master, Liam-kun! She works for the country alongside Lord Shenlong and other familiars, swims in the sea, explores mountains, takes baths, and even naps! Every day is filled with joyous activities. Today, as she snuggles up to her master’s lap, she can’t decide what to play next. Join Chris-chan in her fluffy and delightful everyday life.