Study to Learn About the Safety of Fazirsiran and if it Can Help People With Alpha-1 Antitrypsin Liver Disease With Mild Liver Scarring (Fibrosis)

Inclusion Criteria: * In the opinion of the investigator, the participant is capable of understanding and fully complying with the protocol requirements and adhering to the protocol schedule. * The participant is able to read, understand, and complete the study questionnaires electronically per the investigator's judgment. * The participant signs and dates a written Informed Consent Form (ICF). Any required privacy authorization should also be signed before the initiation of any study procedures. * The participant, of any sex, is aged 18 to 75 years, inclusive. * The participant must have a diagnosis of the protease inhibitor Z mutation (PiZZ) genotype AATD. A diagnosis of PiZZ from source-verifiable medical records is permitted. Otherwise, participants must undergo PiZZ confirmatory testing (genotyping for PiS and PiZ alleles) at screening. PiMZ or PiSZ genotypes are not permitted. * The participant's liver biopsy core samples collected as per protocol requirements. * The participant has evidence of METAVIR stage F1 liver fibrosis, evaluated by a centrally read baseline liver biopsy during the screening period; or confirmed as meeting all the entry criteria by central reading from a previous biopsy conducted within 1 year before the estimated enrollment date using an adequate liver biopsy and slides as defined in the study laboratory manual. * The participant has a pulmonary status that meets the protocol requirements. * It must be confirmed that the participant does not have hepatocellular carcinoma (HCC). * Any participant who is taking statins, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, or beta-1 selective adrenergic receptor inhibitors must have been receiving a stable dose of these medications for at least 8 weeks before randomization. All attempts are to be made for the participant to continue the same dose of the medication for the duration of study participation. * An adult participant must have a body mass index (BMI) between 18 and 39 kilogram per meter square (kg/m\^2), inclusive. * The participant has a 12-lead electrocardiogram at screening that, in the opinion of the investigator, has no abnormalities that could compromise the participant's safety in this study. * The participant is a nonsmoker. * If the participant was being treated with any respiratory medications including inhaled bronchodilators, inhaled anticholinergics, inhaled corticosteroids, or low-dose systemic corticosteroids (prednisone less than or equal to \[\<=10\] milligrams per day \[mg/d\] or its equivalent), the doses of the participant's medications must have remained unchanged for greater than or equal to (\>=) 4 weeks before screening. * The participant must have suitable venous access for blood sampling. * A person of childbearing potential (POCBP) must have a negative serum pregnancy test at screening and a negative urine pregnancy test on Day 1 before dosing. * The participant must use appropriate contraception methods (that is, highly effective methods for female and medically appropriate methods for male study participants) for the entire duration of the study and for 6 months after the last dose of study medication. The participant must not donate sperm for at least 6 months after the last dose of study medication. Exclusion criteria: * The participant has evidence of \>= F2 fibrosis based on liver biopsy during the screening period. * The participant has a history of liver decompensating events. * The participant has a history of varices based on a previous esophagogastroduodenoscopy. * The participant has portal vein thrombosis. * The participant has undergone a prior trans-jugular portosystemic shunt procedure. * The participant has evidence of other forms of chronic liver diseases. * The participant has a history of malignancy within the last 5 years, except for adequately treated basal cell carcinoma, squamous cell skin cancer, superficial bladder tumors, or in situ cervical cancer. Participants with curatively treated malignancies who have no evidence of metastatic disease and disease-free interval greater than (\>) 1 year may be enrolled after approval by the medical monitor. * The participant has an abnormal finding of clinical relevance at the screening evaluation and before administration of the first dose of study dosing that, in the opinion of the investigator, could adversely impact participant safety during the study or adversely impact study results. * The participant has any laboratory abnormalities at screening and before the first dose of the study drug that meet protocol parameters. * The participant is expected to have severe and unavoidable high-level exposure to inhaled pulmonary toxins during the study such as may occur with occupational exposure to mineral dusts or metals. * The participant has a recent lower respiratory tract infection, such as pneumonia, within the last 6 months before screening. The participant may be screened earlier based on principal investigator (PI) assessment of clinical recovery and return to baseline pulmonary function in discussion with the medical monitor. * The participant has a history of frequent pulmonary exacerbations (\>=2 moderate or severe exacerbations within 52 weeks before screening). * The participant is experiencing a pulmonary exacerbation at the time of screening (participant may be rescreened after the clinical resolution of an exacerbation). * The participant is receiving long-term, around-the-clock oxygen supplementation or supplemental oxygen with continuous positive airway pressure (CPAP) or bilevel positive airway pressure for acute respiratory failure. The following conditions are allowable for the participant to enter screening: short-term use of oxygen supplementation (example, for the management of acute chronic obstructive pulmonary disease \[COPD\] exacerbation) or CPAP for obstructive sleep apnea. * The participant has human immunodeficiency virus (HIV) infection as shown by the