Research Study in Japan to Compare Dasiglucagon With Glucagon in Treating Very Low Levels of Blood Sugar in Asian Adults With Type 1 Diabetes and Testing of Dasiglucagon for the Same Condition in Japanese Adolescents

Inclusion Criteria: * For Adults: Asian male or female; For Adolescents: Japanese male or female. * Age at the time of signing the informed consent: For Adults: Age 18-75 years (both inclusive): For Adolescents: Age 12-15 years (both inclusive). * Diagnosed with T1D greater than (\>)1 year before screening. * Glycated haemoglobin (HbA1c) less than (\<)10.0 percentage (%) (86 millimoles per mole \[mmol/mol\]) as assessed by subcontracted laboratory by the site on the day of screening. * For adults: BMI between 18.5 and 29.9 kilogram per meter square (kg/m2) (both inclusive). For adolescents: Body weight greater than or equal to (≥) 33.4 kilograms (kg). * Treated with stable insulin treatment (based on the investigator's discretion preferably no more than a 10-unit daily variation in total daily insulin dose) 30 days prior to screening. * For Japanese participants: Japanese passport or equivalent For non-Japanese participants: Asian (non- Japanese passport or equivalent). Exclusion Criteria: * Known or suspected hypersensitivity to study intervention(s) or related products (glucagon or its derivatives). * Exposure to an investigational medicinal product (IMP) within 30 days or 5 times the half-life of the IMP (if known), whichever is longest before screening. * Severe hypoglycaemia in the last month prior to screening. * Hospitalisation for diabetic ketoacidosis (DKA) in the last month prior to screening. * Presence or history of any clinically relevant respiratory, metabolic, renal, hepatic, gastrointestinal, endocrinological conditions (except conditions associated with diabetes mellitus). * History of epilepsy or seizure disorder. * Known presence or history of pheochromocytoma (i.e., adrenal gland tumour) or insulinoma (i.e., insulin-secreting pancreas tumour). * Clinically significant abnormal electrocardiogram (ECG) at screening as evaluated by investigator. * Any disorder, unwillingness or inability which in the investigator's opinion, might jeopardise the participant's safety or compliance with the protocol. As declared by the participant or in the medical records.